├── .gitignore ├── ActFunc.hpp ├── LICENSE ├── Makefile ├── Matrix.hpp ├── README.md ├── Rand.hpp ├── SkipGram.cpp ├── SkipGram.hpp ├── Utils.hpp ├── Vocabulary.cpp ├── Vocabulary.hpp ├── main.cpp ├── objs └── dummy └── sample_data └── sample.txt /.gitignore: -------------------------------------------------------------------------------- 1 | # Compiled Object files 2 | *.slo 3 | *.lo 4 | *.o 5 | *.obj 6 | 7 | # Precompiled Headers 8 | *.gch 9 | *.pch 10 | 11 | # Compiled Dynamic libraries 12 | *.so 13 | *.dylib 14 | *.dll 15 | 16 | # Fortran module files 17 | *.mod 18 | *.smod 19 | 20 | # Compiled Static libraries 21 | *.lai 22 | *.la 23 | *.a 24 | *.lib 25 | 26 | # Executables 27 | *.exe 28 | *.out 29 | *.app 30 | -------------------------------------------------------------------------------- /ActFunc.hpp: -------------------------------------------------------------------------------- 1 | #pragma once 2 | 3 | #include "Matrix.hpp" 4 | 5 | class ActFunc{ 6 | public: 7 | static Real logistic(const Real x); 8 | }; 9 | 10 | //f(x) = sigm(x) 11 | inline Real ActFunc::logistic(const Real x){ 12 | return 1.0/(1.0+::exp(-x)); 13 | } 14 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | MIT License 2 | 3 | Copyright (c) 2016 Kazuma Hashimoto 4 | 5 | Permission is hereby granted, free of charge, to any person obtaining a copy 6 | of this software and associated documentation files (the "Software"), to deal 7 | in the Software without restriction, including without limitation the rights 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 9 | copies of the Software, and to permit persons to whom the Software is 10 | furnished to do so, subject to the following conditions: 11 | 12 | The above copyright notice and this permission notice shall be included in all 13 | copies or substantial portions of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 | SOFTWARE. 22 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | CXX=g++ 2 | 3 | EIGEN_LOCATION=$$HOME/local/eigen_3.3-beta1 # Modify here to use Eigen 4 | BUILD_DIR=objs 5 | 6 | CXXFLAGS =-Wall 7 | CXXFLAGS+=-O3 8 | CXXFLAGS+=-std=c++11 9 | CXXFLAGS+=-DUSE_FLOAT 10 | CXXFLAGS+=-DUSE_EIGEN_TANH 11 | CXXFLAGS+=-lm 12 | CXXFLAGS+=-funroll-loops 13 | CXXFLAGS+=-march=native 14 | CXXFLAGS+=-m64 15 | CXXFLAGS+=-DEIGEN_DONT_PARALLELIZE 16 | CXXFLAGS+=-DEIGEN_NO_DEBUG 17 | CXXFLAGS+=-DEIGEN_NO_STATIC_ASSERT 18 | CXXFLAGS+=-I$(EIGEN_LOCATION) 19 | CXXFLAGS+=-fopenmp 20 | 21 | SRCS=$(shell ls *.cpp) 22 | OBJS=$(SRCS:.cpp=.o) 23 | 24 | PROGRAM=c2v 25 | 26 | all : $(BUILD_DIR) $(patsubst %,$(BUILD_DIR)/%,$(PROGRAM)) 27 | 28 | $(BUILD_DIR)/%.o : %.cpp 29 | $(CXX) -c $(CXXFLAGS) -o $@ $< 30 | 31 | $(BUILD_DIR)/$(PROGRAM) : $(patsubst %,$(BUILD_DIR)/%,$(OBJS)) 32 | $(CXX) $(CXXFLAGS) $(CXXLIBS) -o $@ $^ 33 | mv $(BUILD_DIR)/$(PROGRAM) ./ 34 | rm -f ?*~ 35 | 36 | clean: 37 | rm -f $(BUILD_DIR)/* $(PROGRAM) ?*~ 38 | echo "dummy" > objs/dummy -------------------------------------------------------------------------------- /Matrix.hpp: -------------------------------------------------------------------------------- 1 | #pragma once 2 | 3 | #include 4 | 5 | #ifdef USE_FLOAT 6 | typedef float Real; 7 | typedef Eigen::MatrixXf MatD; 8 | typedef Eigen::VectorXf VecD; 9 | #else 10 | typedef double Real; 11 | typedef Eigen::MatrixXd MatD; 12 | typedef Eigen::VectorXd VecD; 13 | #endif 14 | 15 | typedef Eigen::Ref RefMatD; 16 | typedef Eigen::Ref RefVecD; 17 | typedef const Eigen::Ref& ConstRefMatD; 18 | typedef const Eigen::Ref& ConstRefVecD; 19 | 20 | typedef Eigen::MatrixXi MatI; 21 | typedef Eigen::VectorXi VecI; 22 | #define REAL_MAX std::numeric_limits::max() 23 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # charNgram2vec 2 | This repository provieds the re-implemented code for pre-training character n-gram embeddings presented in our Joint Many-Task (JMT) paper [1]. 3 | Compared with the original single-thread code used in the paper, in the new version, substantial speedup is achieved (Not yet! Sorry). 4 | Some pre-trained character n-gram embeddings are also available at my project page. 5 | 6 | This project requires a template library for linear algebra, Eigen (http://eigen.tuxfamily.org/index.php?title=Main_Page). Eigen 3.3.XX is recommended.
7 | 8 | ## Usage ## 9 | To use Eigen, please modify the line in Makefile as follows:
10 | EIGEN_LOCATION=$$HOME/local/eigen_3.3-beta1 # Modify here to use Eigen 11 | 12 | More details will come soon! 13 | 14 | ## Reference ## 15 | [1] Kazuma Hashimoto, Caiming Xiong, Yoshimasa Tsuruoka, and Richard Socher. 2017. A Joint Many-Task Model: Growing a Neural Network for Multiple NLP Tasks. In Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing, arXiv cs.CL 1611.01587. 16 | 17 | @InProceedings{hashimoto-jmt:2017:EMNLP2017, 18 | author = {Hashimoto, Kazuma and Xiong, Caiming and Tsuruoka, Yoshimasa and Socher, Richard}, 19 | title = {{A Joint Many-Task Model: Growing a Neural Network for Multiple NLP Tasks}}, 20 | booktitle = {Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing (EMNLP)}, 21 | month = {September}, 22 | year = {2017}, 23 | address = {Copenhagen, Denmark}, 24 | publisher = {Association for Computational Linguistics}, 25 | note = {To appear}, 26 | url = {http://arxiv.org/abs/1611.01587} 27 | } 28 | 29 | ## Licence ## 30 | MIT licence 31 | -------------------------------------------------------------------------------- /Rand.hpp: -------------------------------------------------------------------------------- 1 | #pragma once 2 | 3 | #include "Matrix.hpp" 4 | #include 5 | 6 | class Rand{ 7 | public: 8 | static Rand r_; 9 | 10 | Rand(unsigned long w_ = 88675123): 11 | x(123456789), y(362436069), z(521288629), w(w_) {}; 12 | 13 | unsigned long next(); 14 | Real zero2one(); 15 | void uniform(MatD& mat, const Real scale = 1.0); 16 | void uniform(VecD& vec, const Real scale = 1.0); 17 | Real gauss(Real sigma, Real mu = 0.0); 18 | void gauss(MatD& mat, Real sigma, Real mu = 0.0); 19 | void setMask(VecD& mask, const Real p = 0.5); 20 | template void shuffle(std::vector& data); 21 | template void shuffle(std::vector& data, const unsigned int begin, const unsigned int end); 22 | 23 | private: 24 | unsigned long x; 25 | unsigned long y; 26 | unsigned long z; 27 | unsigned long w; 28 | unsigned long t; //tmp 29 | }; 30 | 31 | inline unsigned long Rand::next(){ 32 | this->t=(this->x^(this->x<<11)); 33 | this->x=this->y; 34 | this->y=this->z; 35 | this->z=this->w; 36 | return (this->w=(this->w^(this->w>>19))^(this->t^(this->t>>8))); 37 | } 38 | 39 | inline Real Rand::zero2one(){ 40 | return ((this->next()&0xFFFF)+1)/65536.0; 41 | } 42 | 43 | inline void Rand::uniform(MatD& mat, const Real scale){ 44 | for (int i = 0; i < mat.rows(); ++i){ 45 | for (int j = 0; j < mat.cols(); ++j){ 46 | mat.coeffRef(i, j) = 2.0*this->zero2one()-1.0; 47 | } 48 | } 49 | 50 | mat *= scale; 51 | } 52 | 53 | inline void Rand::uniform(VecD& vec, const Real scale){ 54 | for (int i = 0; i < vec.rows(); ++i){ 55 | vec.coeffRef(i, 0) = 2.0*this->zero2one()-1.0; 56 | } 57 | 58 | vec *= scale; 59 | } 60 | 61 | inline Real Rand::gauss(Real sigma, Real mu){ 62 | return 63 | mu+ 64 | sigma* 65 | sqrt(-2.0*log(this->zero2one()))* 66 | sin(2.0*M_PI*this->zero2one()); 67 | } 68 | 69 | inline void Rand::gauss(MatD& mat, Real sigma, Real mu){ 70 | for (int i = 0; i < mat.rows(); ++i){ 71 | for (int j = 0; j < mat.cols(); ++j){ 72 | mat.coeffRef(i, j) = this->gauss(sigma, mu); 73 | } 74 | } 75 | } 76 | 77 | inline void Rand::setMask(VecD& mask, const Real p){ 78 | for (int i = 0; i < mask.rows(); ++i){ 79 | mask.coeffRef(i, 0) = (this->zero2one() < p ? 1.0 : 0.0); 80 | } 81 | } 82 | 83 | template inline void Rand::shuffle(std::vector& data){ 84 | T tmp; 85 | 86 | for (int i = data.size(), a, b; i > 1; --i){ 87 | a = i-1; 88 | b = this->next()%i; 89 | tmp = data[a]; 90 | data[a] = data[b]; 91 | data[b] = tmp; 92 | } 93 | } 94 | 95 | template inline void Rand::shuffle(std::vector& data, const unsigned int begin, const unsigned int end){ 96 | T tmp; 97 | 98 | for (int i = end+1, a, b; i > begin+1; --i){ 99 | a = i-1; 100 | b = begin+this->next()%(i-begin); // 0~a -> begin~a= begin+(0~a-begin) 101 | tmp = data[a]; 102 | data[a] = data[b]; 103 | data[b] = tmp; 104 | } 105 | } 106 | -------------------------------------------------------------------------------- /SkipGram.cpp: -------------------------------------------------------------------------------- 1 | #include "SkipGram.hpp" 2 | #include "Utils.hpp" 3 | #include "ActFunc.hpp" 4 | #include 5 | #include 6 | 7 | void SkipGram::init(const int dim, const int windowSize_, const int numNegative_, const std::string& trainFile, const bool train) 8 | { 9 | std::ifstream ifsTrain(trainFile.c_str()); 10 | 11 | this->ngramVector = MatD(dim, this->voc.ngramListCount.size()); 12 | this->scoreVector = MatD::Zero(dim, this->voc.tokenListCount.size()); 13 | this->rndModel.uniform(this->ngramVector, 1.0/dim); 14 | 15 | this->windowSize = windowSize_; 16 | this->numNegative = numNegative_; 17 | 18 | if (!train){ 19 | return; 20 | } 21 | 22 | for (std::string line; std::getline(ifsTrain, line); ){ 23 | if (line == ""){ 24 | continue; 25 | } 26 | 27 | this->trainData.push_back(std::vector()); 28 | this->parse(line, this->trainData.back()); 29 | } 30 | } 31 | 32 | void SkipGram::parse(const std::string& line, std::vector& sentence){ 33 | std::vector tokens; 34 | 35 | sentence.clear(); 36 | Utils::split(line, tokens); 37 | 38 | for (auto it = tokens.begin(); it != tokens.end(); ++it){ 39 | auto it2 = this->voc.tokenIndex.find(*it); 40 | 41 | if (it2 != this->voc.tokenIndex.end()){ 42 | sentence.push_back(it2->second); 43 | } 44 | else { 45 | sentence.push_back(this->voc.unkIndex); 46 | } 47 | } 48 | } 49 | 50 | void SkipGram::train(const Real learningRate){ 51 | static const int glan = 100; 52 | static const int prog = this->trainData.size()/glan; 53 | int count = 0; 54 | Real lr = learningRate; 55 | const Real step = lr/this->trainData.size(); 56 | 57 | this->rndData.shuffle(this->trainData); 58 | 59 | for (int i = 0; i < (int)this->trainData.size(); ++i){ 60 | this->train(this->trainData[i], lr); 61 | lr -= step; 62 | 63 | if ((i+1)%prog == 0 && count < glan){ 64 | std::cout << "\r"; 65 | std::cout << "Training the model... " << ++count << "\%" << std::flush; 66 | } 67 | } 68 | 69 | std::cout << std::endl; 70 | } 71 | 72 | void SkipGram::train(const std::vector& sentence, const Real learningRate){ 73 | for (int i = 0; i < (int)sentence.size(); ++i){ 74 | const int window = (this->rndData.next() >> 16)%this->windowSize+1; 75 | 76 | //omit the UNK token and employ the sub-sampling technique 77 | if (sentence[i] == this->voc.unkIndex || 78 | this->voc.discardProb[sentence[i]] > this->rndData.zero2one()){ 79 | continue; 80 | } 81 | 82 | //left side 83 | for (int j = i-1, count = 0; j >= 0 && count < window; --j){ 84 | //omit the UNK token 85 | if (sentence[j] == this->voc.unkIndex){ 86 | ++count; 87 | continue; 88 | } 89 | 90 | ++count; 91 | this->train(sentence[i], sentence[j], learningRate); 92 | } 93 | 94 | //right side 95 | for (int j = i+1, count = 0; j < (int)sentence.size() && count < window; ++j){ 96 | //omit the UNK token 97 | if (sentence[j] == this->voc.unkIndex){ 98 | ++count; 99 | continue; 100 | } 101 | 102 | ++count; 103 | this->train(sentence[i], sentence[j], learningRate); 104 | } 105 | } 106 | } 107 | 108 | void SkipGram::train(const Vocabulary::INDEX target, const Vocabulary::INDEX context, const Real learningRate){ 109 | static std::unordered_set ngram; 110 | 111 | this->voc.extractCharNgram(this->voc.tokenListCount[target].first, ngram); 112 | this->trainWord(ngram, context, learningRate); 113 | } 114 | 115 | void SkipGram::trainWord(const std::unordered_set& ngram, const Vocabulary::INDEX context, const Real learningRate){ 116 | Real deltaPos, deltaNeg; 117 | Vocabulary::INDEX neg; 118 | std::unordered_set negHist; 119 | static VecD grad(this->ngramVector.rows()); 120 | static VecD target(this->ngramVector.rows()); 121 | 122 | target.setZero(); 123 | for (auto it = ngram.begin(); it != ngram.end(); ++it){ 124 | target += this->ngramVector.col(*it); 125 | } 126 | target.array() /= ngram.size(); 127 | 128 | deltaPos = ActFunc::logistic(target.dot(this->scoreVector.col(context)))-1.0; 129 | grad = deltaPos*this->scoreVector.col(context); 130 | this->scoreVector.col(context) -= (learningRate*deltaPos)*target; 131 | 132 | for (int i = 0; i < this->numNegative; ++i){ 133 | do { 134 | neg = this->voc.noiseDistribution[(this->rndData.next() >> 16)%this->voc.noiseDistribution.size()]; 135 | } while (neg == context || negHist.find(neg) != negHist.end()); 136 | 137 | negHist.insert(neg); 138 | deltaNeg = ActFunc::logistic(target.dot(this->scoreVector.col(neg))); 139 | grad += deltaNeg*this->scoreVector.col(neg); 140 | this->scoreVector.col(neg) -= (learningRate*deltaNeg)*target; 141 | } 142 | 143 | grad.array() /= ngram.size(); 144 | grad.array() *= learningRate; 145 | for (auto it = ngram.begin(); it != ngram.end(); ++it){ 146 | this->ngramVector.col(*it) -= grad; 147 | } 148 | } 149 | 150 | void SkipGram::save(const std::string& fileName){ 151 | std::ofstream ofs((fileName+".model.bin").c_str(), std::ios::out|std::ios::binary); 152 | 153 | assert(ofs); 154 | 155 | Utils::save(ofs, this->ngramVector); 156 | Utils::save(ofs, this->scoreVector); 157 | ofs.close(); 158 | 159 | ofs.open((fileName+".charNgram.txt").c_str()); 160 | for (unsigned int i = 0; i < this->ngramVector.cols(); ++i){ 161 | ofs << this->voc.ngramListCount[i].first; 162 | for (unsigned int j = 0; j < this->ngramVector.rows(); ++j){ 163 | ofs << " " << this->ngramVector.coeff(j, i); 164 | } 165 | ofs << std::endl; 166 | } 167 | } 168 | 169 | void SkipGram::load(const std::string& fileName){ 170 | std::ifstream ifs(fileName.c_str(), std::ios::in|std::ios::binary); 171 | 172 | assert(ifs); 173 | 174 | Utils::load(ifs, this->ngramVector); 175 | Utils::load(ifs, this->scoreVector); 176 | } 177 | -------------------------------------------------------------------------------- /SkipGram.hpp: -------------------------------------------------------------------------------- 1 | #pragma once 2 | 3 | #include "Matrix.hpp" 4 | #include "Rand.hpp" 5 | #include "Vocabulary.hpp" 6 | 7 | class SkipGram{ 8 | public: 9 | SkipGram(Vocabulary& voc_): voc(voc_){}; 10 | 11 | Vocabulary& voc; 12 | Rand rndModel, rndData; 13 | MatD ngramVector; 14 | MatD scoreVector; 15 | 16 | int windowSize; 17 | int numNegative; 18 | 19 | std::vector > trainData; 20 | std::vector > devData; 21 | 22 | void init(const int dim, const int windowSize_, const int numNegative_, const std::string& trainFile, const bool train = true); 23 | void train(const Real learningRate); 24 | void save(const std::string& fileName); 25 | void load(const std::string& fileName); 26 | private: 27 | void parse(const std::string& line, std::vector& sentence); 28 | void train(const std::vector& sentence, const Real learningRate); 29 | void train(const Vocabulary::INDEX target, const Vocabulary::INDEX context, const Real learningRate); 30 | void trainWord(const std::unordered_set& ngram, const Vocabulary::INDEX context, const Real learningRate); 31 | }; 32 | -------------------------------------------------------------------------------- /Utils.hpp: -------------------------------------------------------------------------------- 1 | #pragma once 2 | 3 | #include "Matrix.hpp" 4 | #include 5 | #include 6 | #include 7 | 8 | namespace Utils{ 9 | inline bool isSpace(const char& c){ 10 | return (c == ' ' || c == '\t'); 11 | } 12 | 13 | inline void split(const std::string& str, std::vector& res){ 14 | bool tok = false; 15 | int beg = 0; 16 | 17 | res.clear(); 18 | 19 | for (int i = 0, len = str.length(); i < len; ++i){ 20 | if (!tok && !Utils::isSpace(str[i])){ 21 | beg = i; 22 | tok = true; 23 | } 24 | 25 | if (tok && (i == len-1 || Utils::isSpace(str[i]))){ 26 | tok = false; 27 | res.push_back(isSpace(str[i]) ? str.substr(beg, i-beg) : str.substr(beg, i-beg+1)); 28 | } 29 | } 30 | } 31 | 32 | inline void split(const std::string& str, std::vector& res, const char sep){ 33 | bool tok = false; 34 | int beg = 0; 35 | 36 | res.clear(); 37 | 38 | for (int i = 0, len = str.length(); i < len; ++i){ 39 | if (!tok && str[i] != sep){ 40 | beg = i; 41 | tok = true; 42 | } 43 | 44 | if (tok && (i == len-1 || str[i] == sep)){ 45 | tok = false; 46 | res.push_back((str[i] == sep) ? str.substr(beg, i-beg) : str.substr(beg, i-beg+1)); 47 | } 48 | } 49 | } 50 | 51 | inline void save(std::ofstream& ofs, const MatD& params){ 52 | Real val = 0.0; 53 | 54 | for (int i = 0; i < params.cols(); ++i){ 55 | for (int j = 0; j < params.rows(); ++j){ 56 | val = params.coeff(j, i); 57 | ofs.write((char*)&val, sizeof(Real)); 58 | } 59 | } 60 | } 61 | inline void save(std::ofstream& ofs, const VecD& params){ 62 | Real val = 0.0; 63 | 64 | for (int i = 0; i < params.rows(); ++i){ 65 | val = params.coeff(i, 0); 66 | ofs.write((char*)&val, sizeof(Real)); 67 | } 68 | } 69 | 70 | inline void load(std::ifstream& ifs, MatD& params){ 71 | Real val = 0.0; 72 | 73 | for (int i = 0; i < params.cols(); ++i){ 74 | for (int j = 0; j < params.rows(); ++j){ 75 | ifs.read((char*)&val, sizeof(Real)); 76 | params.coeffRef(j, i) = val; 77 | } 78 | } 79 | } 80 | inline void load(std::ifstream& ifs, VecD& params){ 81 | Real val = 0.0; 82 | 83 | for (int i = 0; i < params.rows(); ++i){ 84 | ifs.read((char*)&val, sizeof(Real)); 85 | params.coeffRef(i, 0) = val; 86 | } 87 | } 88 | 89 | inline void procArg(int argc, char** argv, int& embeddingDim, int& windowSize, int& numNegative, Real& learningRate, int& wminFreq, int& cminFreq, std::string& trainFile, std::string& outputFile){ 90 | for (int i = 1; i < argc; i+=2){ 91 | std::string arg = (std::string)argv[i]; 92 | 93 | if (arg == "-help"){ 94 | printf("### Options ###\n"); 95 | printf("-edim the dimensionality of embeddings (default: 100)\n"); 96 | printf("-window the context window size (default: 1)\n"); 97 | printf("-neg the number of negative samples for negative sampling learning (default: 15)\n"); 98 | printf("-lr the initial learning rate (default: 0.025)\n"); 99 | printf("-wminfreq the threshold to cut rare words (default: 10)\n"); 100 | printf("-cminfreq the threshold to cut rare char n-grams (default: 10)\n"); 101 | printf("-train the file name for training (default: ./sample_data/sample.txt)\n"); 102 | printf("-output the file name for output files (default: ./result)\n"); 103 | exit(1); 104 | } 105 | else if (arg == "-edim"){ 106 | assert(i+1 < argc); 107 | embeddingDim = atoi(argv[i+1]); 108 | assert(embeddingDim > 0); 109 | } 110 | else if (arg == "-window"){ 111 | assert(i+1 < argc); 112 | windowSize = atoi(argv[i+1]); 113 | assert(windowSize > 0); 114 | } 115 | else if (arg == "-neg"){ 116 | assert(i+1 < argc); 117 | numNegative = atoi(argv[i+1]); 118 | assert(numNegative > 0); 119 | } 120 | else if (arg == "-lr"){ 121 | assert(i+1 < argc); 122 | learningRate = atof(argv[i+1]); 123 | assert(learningRate > 0.0); 124 | } 125 | else if (arg == "-wminfreq"){ 126 | assert(i+1 < argc); 127 | wminFreq = atoi(argv[i+1]); 128 | assert(wminFreq > 0); 129 | } 130 | else if (arg == "-cminfreq"){ 131 | assert(i+1 < argc); 132 | cminFreq = atoi(argv[i+1]); 133 | assert(cminFreq > 0); 134 | } 135 | else if (arg == "-train"){ 136 | assert(i+1 < argc); 137 | trainFile = (std::string)argv[i+1]; 138 | } 139 | else if (arg == "-output"){ 140 | assert(i+1 < argc); 141 | outputFile = (std::string)argv[i+1]; 142 | } 143 | } 144 | } 145 | }; 146 | -------------------------------------------------------------------------------- /Vocabulary.cpp: -------------------------------------------------------------------------------- 1 | #include "Vocabulary.hpp" 2 | #include "Utils.hpp" 3 | #include 4 | 5 | struct sort_pred { 6 | bool operator()(const std::pair &left, const std::pair &right) { 7 | return left.second > right.second; 8 | } 9 | }; 10 | 11 | void Vocabulary::extractCharNgram(const std::string& str, std::unordered_map& ngramCount){ 12 | const std::string prefix = "#BEGIN#"; 13 | const std::string suffix = "#END#"; 14 | const unsigned int len = str.length(); 15 | 16 | //unigram 17 | const std::string uni = "1gram-"; 18 | for (unsigned int i = 0; i < len; ++i){ 19 | const std::string entry = uni+str.substr(i, 1); 20 | auto it = ngramCount.find(entry); 21 | 22 | if (it == ngramCount.end()){ 23 | ngramCount[entry] = 1; 24 | } 25 | else { 26 | it->second += 1; 27 | } 28 | } 29 | 30 | //bigram 31 | const std::string bi = "2gram-"; 32 | for (unsigned int i = 0; i <= len; ++i){ 33 | std::string entry; 34 | if (i == 0){ 35 | entry = bi+prefix+str.substr(i, 1); 36 | } 37 | else if (i == len){ 38 | entry = bi+str.substr(i-1, 1)+suffix; 39 | } 40 | else { 41 | entry = bi+str.substr(i-1, 2); 42 | } 43 | 44 | auto it = ngramCount.find(entry); 45 | if (it == ngramCount.end()){ 46 | ngramCount[entry] = 1; 47 | } 48 | else { 49 | it->second += 1; 50 | } 51 | } 52 | 53 | //trigram 54 | const std::string tri = "3gram-"; 55 | for (unsigned int i = 0; i < len; ++i){ 56 | std::string entry; 57 | if (i == 0){ 58 | if (len == 1){ 59 | entry = tri+prefix+str+suffix; 60 | } 61 | else { 62 | entry = tri+prefix+str.substr(i, 2); 63 | } 64 | } 65 | else if (i == len-1){ 66 | entry = tri+str.substr(i-1, 2)+suffix; 67 | } 68 | else { 69 | entry = tri+str.substr(i-1, 3); 70 | } 71 | 72 | auto it = ngramCount.find(entry); 73 | if (it == ngramCount.end()){ 74 | ngramCount[entry] = 1; 75 | } 76 | else { 77 | it->second += 1; 78 | } 79 | } 80 | 81 | //fourgram 82 | if (len < 2){ 83 | return; 84 | } 85 | const std::string four = "4gram-"; 86 | for (unsigned int i = 0; i < len-1; ++i){ 87 | std::string entry; 88 | if (i == 0){ 89 | if (len == 2){ 90 | entry = four+prefix+str+suffix; 91 | } 92 | else { 93 | entry = four+prefix+str.substr(i, 3); 94 | } 95 | } 96 | else if (i == len-2){ 97 | entry = four+str.substr(i-1, 3)+suffix; 98 | } 99 | else { 100 | entry = four+str.substr(i-1, 4); 101 | } 102 | 103 | auto it = ngramCount.find(entry); 104 | if (it == ngramCount.end()){ 105 | ngramCount[entry] = 1; 106 | } 107 | else { 108 | it->second += 1; 109 | } 110 | } 111 | } 112 | 113 | void Vocabulary::extractCharNgram(const std::string& str, std::unordered_set& ngram){ 114 | const std::string prefix = "#BEGIN#"; 115 | const std::string suffix = "#END#"; 116 | const unsigned int len = str.length(); 117 | 118 | ngram.clear(); 119 | 120 | //unigram 121 | const std::string uni = "1gram-"; 122 | for (unsigned int i = 0; i < len; ++i){ 123 | const std::string entry = uni+str.substr(i, 1); 124 | auto it = this->ngramIndex.find(entry); 125 | 126 | if (it == this->ngramIndex.end()){ 127 | continue; 128 | } 129 | 130 | ngram.insert(it->second); 131 | } 132 | 133 | //bigram 134 | const std::string bi = "2gram-"; 135 | for (unsigned int i = 0; i <= len; ++i){ 136 | std::string entry; 137 | if (i == 0){ 138 | entry = bi+prefix+str.substr(i, 1); 139 | } 140 | else if (i == len){ 141 | entry = bi+str.substr(i-1, 1)+suffix; 142 | } 143 | else { 144 | entry = bi+str.substr(i-1, 2); 145 | } 146 | 147 | auto it = this->ngramIndex.find(entry); 148 | 149 | if (it == this->ngramIndex.end()){ 150 | continue; 151 | } 152 | 153 | ngram.insert(it->second); 154 | } 155 | 156 | //trigram 157 | const std::string tri = "3gram-"; 158 | for (unsigned int i = 0; i < len; ++i){ 159 | std::string entry; 160 | if (i == 0){ 161 | if (len == 1){ 162 | entry = tri+prefix+str+suffix; 163 | } 164 | else { 165 | entry = tri+prefix+str.substr(i, 2); 166 | } 167 | } 168 | else if (i == len-1){ 169 | entry = tri+str.substr(i-1, 2)+suffix; 170 | } 171 | else { 172 | entry = tri+str.substr(i-1, 3); 173 | } 174 | 175 | auto it = this->ngramIndex.find(entry); 176 | 177 | if (it == this->ngramIndex.end()){ 178 | continue; 179 | } 180 | 181 | ngram.insert(it->second); 182 | } 183 | 184 | //fourgram 185 | if (len < 2){ 186 | return; 187 | } 188 | const std::string four = "4gram-"; 189 | for (unsigned int i = 0; i < len-1; ++i){ 190 | std::string entry; 191 | if (i == 0){ 192 | if (len == 2){ 193 | entry = four+prefix+str+suffix; 194 | } 195 | else { 196 | entry = four+prefix+str.substr(i, 3); 197 | } 198 | } 199 | else if (i == len-2){ 200 | entry = four+str.substr(i-1, 3)+suffix; 201 | } 202 | else { 203 | entry = four+str.substr(i-1, 4); 204 | } 205 | 206 | auto it = this->ngramIndex.find(entry); 207 | 208 | if (it == this->ngramIndex.end()){ 209 | continue; 210 | } 211 | 212 | ngram.insert(it->second); 213 | } 214 | } 215 | 216 | Vocabulary::Vocabulary(const std::string& inputFile, const Vocabulary::COUNT wordFreqThreshold, const Vocabulary::COUNT nGramFreqThreshold){ 217 | std::ifstream ifs(inputFile.c_str()); 218 | std::vector tokens; 219 | std::unordered_map tokenCountMap; 220 | std::unordered_map ngramCountMap; 221 | Vocabulary::COUNT totalCount = 0; 222 | 223 | std::cout << "Building the vocabulary..." << std::flush; 224 | 225 | for (std::string line; std::getline(ifs, line); ){ 226 | if (line == ""){ 227 | continue; 228 | } 229 | 230 | Utils::split(line, tokens); 231 | 232 | for (auto it = tokens.begin(); it != tokens.end(); ++it){ 233 | //process ngrams 234 | this->extractCharNgram(*it, ngramCountMap); 235 | 236 | //process word 237 | auto it2 = tokenCountMap.find(*it); 238 | 239 | if (it2 == tokenCountMap.end()){ 240 | tokenCountMap[*it] = 1; 241 | } 242 | else { 243 | tokenCountMap.at(*it) += 1; 244 | } 245 | } 246 | } 247 | 248 | //select frequent words 249 | for (auto it = tokenCountMap.begin(); it != tokenCountMap.end(); ++it){ 250 | if (it->second >= wordFreqThreshold){ 251 | this->tokenListCount.push_back(std::pair(it->first, it->second)); 252 | } 253 | 254 | totalCount += it->second; 255 | } 256 | this->unkIndex = this->tokenListCount.size(); 257 | 258 | //select frequent ngrams 259 | for (auto it = ngramCountMap.begin(); it != ngramCountMap.end(); ++it){ 260 | if (it->second >= nGramFreqThreshold){ 261 | this->ngramListCount.push_back(std::pair(it->first, it->second)); 262 | } 263 | } 264 | 265 | //Sort by frequency 266 | std::sort(this->tokenListCount.begin(), this->tokenListCount.end(), sort_pred()); 267 | std::sort(this->ngramListCount.begin(), this->ngramListCount.end(), sort_pred()); 268 | 269 | for (Vocabulary::INDEX i = 0; i < this->tokenListCount.size(); ++i){ 270 | this->tokenIndex[this->tokenListCount[i].first] = i; 271 | 272 | for (Vocabulary::COUNT j = 0, numNoise = (Vocabulary::COUNT)pow(this->tokenListCount[i].second, 0.75); j < numNoise; ++j){ 273 | this->noiseDistribution.push_back(i); 274 | } 275 | } 276 | 277 | for (Vocabulary::INDEX i = 0; i < this->ngramListCount.size(); ++i){ 278 | this->ngramIndex[this->ngramListCount[i].first] = i; 279 | } 280 | 281 | for (auto it = tokenListCount.begin(); it != this->tokenListCount.end(); ++it){ 282 | this->discardProb.push_back((Real)it->second/totalCount); 283 | this->discardProb.back() = 1.0-sqrt(1.0e-05/this->discardProb.back()); 284 | } 285 | 286 | std::vector().swap(tokens); 287 | std::unordered_map().swap(tokenCountMap); 288 | std::unordered_map().swap(ngramCountMap); 289 | 290 | std::cout << " Done!" << std::endl; 291 | } 292 | -------------------------------------------------------------------------------- /Vocabulary.hpp: -------------------------------------------------------------------------------- 1 | #pragma once 2 | 3 | #include 4 | #include 5 | #include 6 | #include 7 | #include "Matrix.hpp" 8 | 9 | class Vocabulary{ 10 | public: 11 | 12 | typedef unsigned int INDEX; 13 | typedef unsigned long int COUNT; 14 | 15 | Vocabulary(){}; 16 | Vocabulary(const std::string& inputFile, const Vocabulary::COUNT wordFreqThreshold, const Vocabulary::COUNT nGramFreqThreshold); 17 | 18 | std::unordered_map tokenIndex; 19 | std::vector > tokenListCount; 20 | Vocabulary::INDEX unkIndex; 21 | 22 | std::unordered_map ngramIndex; 23 | std::vector > ngramListCount; 24 | 25 | std::vector noiseDistribution; 26 | std::vector discardProb; 27 | 28 | void extractCharNgram(const std::string& str, std::unordered_set& ngram); 29 | 30 | private: 31 | void extractCharNgram(const std::string& str, std::unordered_map& ngramCount); 32 | }; 33 | -------------------------------------------------------------------------------- /main.cpp: -------------------------------------------------------------------------------- 1 | #include "Vocabulary.hpp" 2 | #include "SkipGram.hpp" 3 | #include "Utils.hpp" 4 | #include 5 | 6 | int main(int argc, char** argv){ 7 | int dim = 100; 8 | int windowSize = 1; 9 | int numNegative = 15; 10 | Real learningRate = 0.025; 11 | int wordFreqThreshold = 10; 12 | int nGramFreqThreshold = 10; 13 | std::string trainFile = "./sample_data/sample.txt"; 14 | std::string outputFile = "./result"; 15 | 16 | Utils::procArg(argc, argv, 17 | dim, windowSize, numNegative, learningRate, 18 | wordFreqThreshold, nGramFreqThreshold, 19 | trainFile, outputFile); 20 | 21 | printf("### Settings ###\n"); 22 | printf("-edim %d\n", dim); 23 | printf("-window %d\n", windowSize); 24 | printf("-neg %d\n", numNegative); 25 | printf("-lr %f\n", learningRate); 26 | printf("-wminfreq %d\n", wordFreqThreshold); 27 | printf("-cminfreq %d\n", nGramFreqThreshold); 28 | printf("-train %s\n", trainFile.c_str()); 29 | printf("-output %s\n", outputFile.c_str()); 30 | puts(""); 31 | 32 | Vocabulary voc; 33 | SkipGram sg(voc); 34 | 35 | voc = Vocabulary(trainFile, wordFreqThreshold, nGramFreqThreshold); 36 | std::cout << "Word vocabulary size:\t" << voc.tokenListCount.size() << std::endl; 37 | std::cout << "Ngram Vocabulary size:\t" << voc.ngramListCount.size() << std::endl; 38 | 39 | sg.init(dim, windowSize, numNegative, trainFile, true); 40 | sg.train(learningRate); 41 | 42 | std::cout << "Done!" << std::endl; 43 | 44 | sg.save(outputFile); 45 | 46 | return 0; 47 | } 48 | -------------------------------------------------------------------------------- /objs/dummy: -------------------------------------------------------------------------------- 1 | dummy 2 | -------------------------------------------------------------------------------- /sample_data/sample.txt: -------------------------------------------------------------------------------- 1 | Anarchism 2 | Anarchism is a political philosophy that advocates stateless societies based on non-hierarchical free associations . 3 | Anarchism holds the state to be undesirable , unnecessary , or harmful . 4 | While anti-statism is central , some argue that anarchism entails opposing authority or hierarchical organization in the conduct of human relations , including , but not limited to , the state system . 5 | As a subtle and anti-dogmatic philosophy , anarchism draws on many currents of thought and strategy . 6 | Anarchism does not offer a fixed body of doctrine from a single particular world view , instead fluxing and flowing as a philosophy . 7 | There are many types and traditions of anarchism , not all of which are mutually exclusive . 8 | Anarchist schools of thought can differ fundamentally , supporting anything from extreme individualism to complete collectivism . 9 | Strains of anarchism have often been divided into the categories of social and individualist anarchism or similar dual classifications . 10 | Anarchism is often considered a radical left-wing ideology , and much of anarchist economics and anarchist legal philosophy reflect anti-authoritarian interpretations of communism , collectivism , syndicalism , mutualism , or participatory economics . 11 | Anarchism as a mass social movement has regularly endured fluctuations in popularity . 12 | The central tendency of anarchism as a social movement has been represented by anarcho-communism and anarcho-syndicalism , with individualist anarchism being primarily a literary phenomenon which nevertheless did have an impact on the bigger currents and individualists have also participated in large anarchist organizations . 13 | Many anarchists oppose all forms of aggression , supporting self-defense or non-violence ( anarcho-pacifism ) , while others have supported the use of some coercive measures , including violent revolution and propaganda of the deed , on the path to an anarchist society . 14 | Etymology and terminology . 15 | The term " anarchism " is a compound word composed from the word " anarchy " and the suffix " -ism " , themselves derived respectively from the Greek , i.e. " anarchy " ( from , " anarchos " , meaning " one without rulers " ; from the privative prefix <1F00> nu- ( " an- " , i.e. " without " ) + , " archos " , i.e. " leader " , " ruler " ; ( cf. " archon " or , " arkhe " , i.e. " authority " , " sovereignty " , " realm " , " magistracy " ) ) and the suffix or ( " -ismos " , " -isma " , from the verbal infinitive suffix -iotazetaepsiloniotanu , " -izein " ) . 16 | The first known use of this word was in 1539 . 17 | " Anarchists " was the term adopted by Maximilien de Robespierre to attack those on the left whom he had used for his own ends during the French Revolution but was determined to get rid of , though among these " anarchists " there were few who exhibited the social revolt characteristics of later anarchists . 18 | There would be many revolutionaries of the early nineteenth century who contributed to the anarchist doctrines of the next generation , such as William Godwin and Wilhelm Weitling , but they did not use the word " anarchist " or " anarchism " in describing themselves or their beliefs . 19 | Pierre-Joseph Proudhon was the first political philosopher to call himself an anarchist , making the formal birth of anarchism the mid-nineteenth century . 20 | Since the 1890s from France , the term " libertarianism " has often been used as a synonym for anarchism and was used almost exclusively in this sense until the 1950s in the United States ; its use as a synonym is still common outside the United States . 21 | On the other hand , some use " libertarianism " to refer to individualistic free-market philosophy only , referring to free-market anarchism as " libertarian anarchism " . 22 | History . 23 | Origins . 24 | The earliest anarchist themes can be found in the 6th century BC , among the works of Taoist philosopher Laozi , and in later centuries by Zhuangzi and Bao Jingyan . 25 | Zhuangzi 's philosophy has been described by various sources as anarchist . 26 | Zhuangzi wrote , " A petty thief is put in jail . 27 | A great brigand becomes a ruler of a Nation. " Diogenes of Sinope and the Cynics , their contemporary Zeno of Citium , the founder of Stoicism , also introduced similar topics . 28 | Jesus is sometimes considered the first anarchist in the Christian anarchist tradition . 29 | Georges Lechartier wrote that " The true founder of anarchy was Jesus Christ and ... the first anarchist society was that of the apostles. " Such a distinction reverberates subversive religious conceptions like the aforementioned seemingly anarchistic Taoist teachings and that of other anti-authoritarian religious traditions creating a complex relationship regarding the question as to whether or not anarchism and religion are compatible . 30 | This is exemplified when the glorification of the state is viewed as a form of sinful idolatry . 31 | The French renaissance political philosopher Etienne de La Boetie has been said to write an important anarchist precedent in his most famous work the " Discourse on Voluntary Servitude " . 32 | The radical Protestant Christian Gerrard Winstanley and his group the Diggers are cited by various authors as proposing anarchist social measures in the 17th century in England . 33 | The term " anarchist " first entered the English language in 1642 , during the English Civil War , as a term of abuse , used by Royalists against their Roundhead opponents . 34 | By the time of the French Revolution some , such as the " Enrages " , began to use the term positively , in opposition to Jacobin centralisation of power , seeing " revolutionary government " as oxymoronic . 35 | By the turn of the 19th century , the English word " anarchism " had lost its initial negative connotation . 36 | Modern anarchism sprang from the secular or religious thought of the Enlightenment , particularly Jean-Jacques Rousseau 's arguments for the moral centrality of freedom . 37 | There were a variety of anarchist currents during the French Revolution , with some revolutionaries using the term " " anarchiste " " in a positive light as early as September 1793 . 38 | The " enrages " opposed revolutionary government as a contradiction in terms . 39 | Denouncing the Jacobin dictatorship , Jean Varlet wrote in 1794 that " government and revolution are incompatible , unless the people wishes to set its constituted authorities in permanent insurrection against itself. " During the French Revolution , Sylvain Marechal , in his " Manifesto of the Equals " ( 1796 ) , demanded " the communal enjoyment of the fruits of the earth " and looked forward to the disappearance of " the revolting distinction of rich and poor , of great and small , of masters and valets , of governors and governed. " From this climate William Godwin developed what many consider the first expression of modern anarchist thought . 40 | Godwin was , according to Peter Kropotkin , " the first to formulate the political and economical conceptions of anarchism , even though he did not give that name to the ideas developed in his work " , while Godwin attached his anarchist ideas to an early Edmund Burke . 41 | Benjamin Tucker instead credits Josiah Warren , an American who promoted stateless and voluntary communities where all goods and services were private , with being " the first man to expound and formulate the doctrine now known as Anarchism. " The first to describe himself as an anarchist was Pierre-Joseph Proudhon , a French philosopher and politician , which led some to call him the founder of modern anarchist theory . 42 | The anarcho-communist Joseph Dejacque was the first person to describe himself as " libertarian " . 43 | Unlike Proudhon , he argued that , " it is not the product of his or her labor that the worker has a right to , but to the satisfaction of his or her needs , whatever may be their nature. " Anarchists active in the 1848 Revolution in France , included Anselme Bellegarrigue , Ernest Coeurderoy , Joseph Dejacque and Pierre Joseph Proudhon . 44 | First International and the Paris Commune . 45 | In Europe , harsh reaction followed the revolutions of 1848 , during which ten countries had experienced brief or long-term social upheaval as groups carried out nationalist uprisings . 46 | After most of these attempts at systematic change ended in failure , conservative elements took advantage of the divided groups of socialists , anarchists , liberals , and nationalists , to prevent further revolt . 47 | In 1864 the International Workingmen 's Association ( sometimes called the " First International " ) united diverse revolutionary currents including French followers of Proudhon , Blanquists , Philadelphes , English trade unionists , socialists and social democrats . 48 | Due to its links to active workers ' movements , the International became a significant organization . 49 | Karl Marx became a leading figure in the International and a member of its General Council . 50 | Proudhon 's followers , the mutualists , opposed Marx 's state socialism , advocating political abstentionism and small property holdings . 51 | In 1868 , following their unsuccessful participation in the League of Peace and Freedom ( LPF ) , Russian revolutionary Mikhail Bakunin and his collectivist anarchist associates joined the First International ( which had decided not to get involved with the LPF ) . 52 | They allied themselves with the federalist socialist sections of the International , who advocated the revolutionary overthrow of the state and the collectivization of property . 53 | At first , the collectivists worked with the Marxists to push the First International in a more revolutionary socialist direction . 54 | Subsequently , the International became polarised into two camps , with Marx and Bakunin as their respective figureheads . 55 | Bakunin characterised Marx 's ideas as centralist and predicted that , if a Marxist party came to power , its leaders would simply take the place of the ruling class they had fought against . 56 | Anarchist historian George Woodcock reports that " The annual Congress of the International had not taken place in 1870 owing to the outbreak of the Paris Commune , and in 1871 the General Council called only a special conference in London . 57 | One delegate was able to attend from Spain and none from Italy , while a technical excuse - that they had split away from the Federation Romande - was used to avoid inviting Bakunin 's Swiss supporters . 58 | Thus only a tiny minority of anarchists was present , and the General Council 's resolutions passed almost unanimously . 59 | Most of them were clearly directed against Bakunin and his followers. " In 1872 , the conflict climaxed with a final split between the two groups at the Hague Congress , where Bakunin and James Guillaume were expelled from the International and its headquarters were transferred to New York . 60 | In response , the federalist sections formed their own International at the St . 61 | Imier Congress , adopting a revolutionary anarchist program . 62 | The Paris Commune was a government that briefly ruled Paris from 18 March ( more formally , from 28 March ) to 28 May 1871 . 63 | The Commune was the result of an uprising in Paris after France was defeated in the Franco-Prussian War . 64 | Anarchists participated actively in the establishment of the Paris Commune . 65 | They included George Woodcock manifests that 66 | 67 | Organized labour . 68 | The anti-authoritarian sections of the First International were the precursors of the anarcho-syndicalists , seeking to " replace the privilege and authority of the State " with the " free and spontaneous organization of labor. " In 1886 , the Federation of Organized Trades and Labor Unions ( FOTLU ) of the United States and Canada unanimously set 1 May 1886 , as the date by which the eight-hour work day would become standard . 69 | In response , unions across the United States prepared a general strike in support of the event . 70 | On 3 May , in Chicago , a fight broke out when strikebreakers attempted to cross the picket line , and two workers died when police opened fire upon the crowd . 71 | The next day , 4 May , anarchists staged a rally at Chicago 's Haymarket Square . 72 | A bomb was thrown by an unknown party near the conclusion of the rally , killing an officer . 73 | In the ensuing panic , police opened fire on the crowd and each other . 74 | Seven police officers and at least four workers were killed . 75 | Eight anarchists directly and indirectly related to the organisers of the rally were arrested and charged with the murder of the deceased officer . 76 | The men became international political celebrities among the labour movement . 77 | Four of the men were executed and a fifth committed suicide prior to his own execution . 78 | The incident became known as the Haymarket affair , and was a setback for the labour movement and the struggle for the eight-hour day . 79 | In 1890 a second attempt , this time international in scope , to organise for the eight-hour day was made . 80 | The event also had the secondary purpose of memorializing workers killed as a result of the Haymarket affair . 81 | Although it had initially been conceived as a once-off event , by the following year the celebration of International Workers ' Day on May Day had become firmly established as an international worker 's holiday . 82 | In 1907 , the International Anarchist Congress of Amsterdam gathered delegates from 14 different countries , among which important figures of the anarchist movement , including Errico Malatesta , Pierre Monatte , Luigi Fabbri , Benoit Broutchoux , Emma Goldman , Rudolf Rocker , and Christiaan Cornelissen . 83 | Various themes were treated during the Congress , in particular concerning the organisation of the anarchist movement , popular education issues , the general strike or antimilitarism . 84 | A central debate concerned the relation between anarchism and syndicalism ( or trade unionism ) . 85 | Malatesta and Monatte were in particular disagreement themselves on this issue , as the latter thought that syndicalism was revolutionary and would create the conditions of a social revolution , while Malatesta did not consider syndicalism by itself sufficient . 86 | He thought that the trade-union movement was reformist and even conservative , citing as essentially bourgeois and anti-worker the phenomenon of professional union officials . 87 | Malatesta warned that the syndicalists aims were in perpetuating syndicalism itself , whereas anarchists must always have anarchy as their end and consequently refrain from committing to any particular method of achieving it . 88 | The Spanish Workers Federation in 1881 was the first major anarcho-syndicalist movement ; anarchist trade union federations were of special importance in Spain . 89 | The most successful was the Confederacion Nacional del Trabajo ( National Confederation of Labour : CNT ) , founded in 1910 . 90 | Before the 1940s , the CNT was the major force in Spanish working class politics , attracting 1.58 million members at one point and playing a major role in the Spanish Civil War . 91 | The CNT was affiliated with the International Workers Association , a federation of anarcho-syndicalist trade unions founded in 1922 , with delegates representing two million workers from 15 countries in Europe and Latin America . 92 | In Latin America in particular " The anarchists quickly became active in organizing craft and industrial workers throughout South and Central America , and until the early 1920s most of the trade unions in Mexico , Brazil , Peru , Chile , and Argentina were anarcho-syndicalist in general outlook ; the prestige of the Spanish C.N.T. as a revolutionary organization was 93 | undoubtedly to a great extent responsible for this situation . 94 | The largest and most militant of these organizations was the Federacion Obrera Regional Argentina ... 95 | it grew quickly 96 | to a membership of nearly a quarter of a million , which dwarfed the rival socialdemocratic unions . " 97 | Propaganda of the deed and illegalism . 98 | Some anarchists , such as Johann Most , advocated publicizing violent acts of retaliation against counter-revolutionaries because " we preach not only action in and for itself , but also action as propaganda. " By the 1880s , people inside and outside the anarchist movement began to use the slogan , " propaganda of the deed " to refer to individual bombings , regicides , and tyrannicides . 99 | From 1905 onwards , the Russian counterparts of these anti-syndicalist anarchist-communists become partisans of economic terrorism and illegal ' expropriations'. " Illegalism as a practice emerged and within it " The acts of the anarchist bombers and assassins ( " propaganda by the deed " ) and the anarchist burglars ( " individual reappropriation " ) expressed their desperation and their personal , violent rejection of an intolerable society . 100 | Moreover , they were clearly meant to be " exemplary " invitations to revolt. " . 101 | France 's Bonnot Gang was the most famous group to embrace illegalism . 102 | However , as soon as 1887 , important figures in the anarchist movement distanced themselves from such individual acts . 103 | Peter Kropotkin thus wrote that year in " Le Revolte " that " a structure based on centuries of history can not be destroyed with a few kilos of dynamite " . 104 | A variety of anarchists advocated the abandonment of these sorts of tactics in favor of collective revolutionary action , for example through the trade union movement . 105 | The anarcho-syndicalist , Fernand Pelloutier , argued in 1895 for renewed anarchist involvement in the labor movement on the basis that anarchism could do very well without " the individual dynamiter . " 106 | State repression ( including the infamous 1894 French " lois scelerates " ) of the anarchist and labor movements following the few successful bombings and assassinations may have contributed to the abandonment of these kinds of tactics , although reciprocally state repression , in the first place , may have played a role in these isolated acts . 107 | The dismemberment of the French socialist movement , into many groups and , following the suppression of the 1871 Paris Commune , the execution and exile of many " communards " to penal colonies , favored individualist political expression and acts . 108 | Numerous heads of state were assassinated between 1881 and 1914 by members of the anarchist movement . 109 | For example , U.S . 110 | President McKinley 's assassin Leon Czolgosz claimed to have been influenced by anarchist and feminist Emma Goldman . 111 | Bombings were associated in the media with anarchists because international terrorism arose during this time period with the widespread distribution of dynamite . 112 | This image remains to this day . 113 | Propaganda of the deed was abandoned by the vast majority of the anarchist movement after World War I ( 1914-1918 ) and the 1917 October Revolution . 114 | Russian Revolution and other uprisings of the 1910s . 115 | Anarchists participated alongside the Bolsheviks in both February and October revolutions , and were initially enthusiastic about the Bolshevik revolution . 116 | However , following a political falling out with the Bolsheviks by the anarchists and other left-wing opposition , the conflict culminated in the 1921 Kronstadt rebellion , which the new government repressed . 117 | Anarchists in central Russia were either imprisoned , driven underground or joined the victorious Bolsheviks ; the anarchists from Petrograd and Moscow fled to the Ukraine . 118 | There , in the Free Territory , they fought in the civil war against the Whites ( a grouping of monarchists and other opponents of the October Revolution ) and then the Bolsheviks as part of the Revolutionary Insurrectionary Army of Ukraine led by Nestor Makhno , who established an anarchist society in the region for a number of months . 119 | Expelled American anarchists Emma Goldman and Alexander Berkman were amongst those agitating in response to Bolshevik policy and the suppression of the Kronstadt uprising , before they left Russia . 120 | Both wrote accounts of their experiences in Russia , criticizing the amount of control the Bolsheviks exercised . 121 | For them , Bakunin 's predictions about the consequences of Marxist rule that the rulers of the new " socialist " Marxist state would become a new elite had proved all too true . 122 | The victory of the Bolsheviks in the October Revolution and the resulting Russian Civil War did serious damage to anarchist movements internationally . 123 | Many workers and activists saw Bolshevik success as setting an example ; Communist parties grew at the expense of anarchism and other socialist movements . 124 | In France and the United States , for example , members of the major syndicalist movements of the CGT and IWW left the organizations and joined the Communist International . 125 | The revolutionary wave of 1917-23 saw the active participation of anarchists in varying degrees of protagonism . 126 | In the German uprising known as the German Revolution of 1918-1919 which established the Bavarian Soviet Republic the anarchists Gustav Landauer , Silvio Gesell and Erich Muhsam had important leadership positions within the revolutionary councilist structures . 127 | In the Italian events known as the " biennio rosso " the anarcho-syndicalist trade union Unione Sindacale Italiana " grew to 800,000 members and the influence of the Italian Anarchist Union ( 20,000 members plus " Umanita Nova " , its daily paper ) grew accordingly ... 128 | Anarchists were the first to suggest occupying workplaces . 129 | In the Mexican Revolution the Mexican Liberal Party was established and during the early 1910s it lead a series of military offensives leading to the conquest and occupation of certain towns and districts in Baja California with the leadership of anarcho-communist Ricardo Flores Magon . 130 | In Paris , the Dielo Truda group of Russian anarchist exiles , which included Nestor Makhno , concluded that anarchists needed to develop new forms of organisation in response to the structures of Bolshevism . 131 | Their 1926 manifesto , called the " Organizational Platform of the General Union of Anarchists (Draft) " , was supported . 132 | Platformist groups active today include the Workers Solidarity Movement in Ireland and the North Eastern Federation of Anarchist Communists of North America . 133 | Synthesis anarchism emerged as an organizational alternative to platformism that tries to join anarchists of different tendencies under the principles of anarchism without adjectives . 134 | In the 1920s this form found as its main proponents Volin and Sebastien Faure . 135 | It is the main principle behind the anarchist federations grouped around the contemporary global International of Anarchist Federations . 136 | Conflicts with European fascist regimes . 137 | In the 1920s and 1930s , the rise of fascism in Europe transformed anarchism 's conflict with the state . 138 | Italy saw the first struggles between anarchists and fascists . 139 | Italian anarchists played a key role in the anti-fascist organisation " Arditi del Popolo " , which was strongest in areas with anarchist traditions , and achieved some success in their activism , such as repelling Blackshirts in the anarchist stronghold of Parma in August 1922 . 140 | The veteran Italian anarchist , Luigi Fabbri , was one of the first critical theorists of fascism , describing it as " the preventive counter-revolution. " In France , where the far right leagues came close to insurrection in the February 1934 riots , anarchists divided over a united front policy . 141 | Anarchists in France and Italy were active in the Resistance during World War II . 142 | In Germany the anarchist Erich Muhsam was arrested on charges unknown in the early morning hours of 28 February 1933 , within a few hours after the Reichstag fire in Berlin . 143 | Joseph Goebbels , the Nazi propaganda minister , labelled him as one of " those Jewish subversives. " Over the next seventeen months , he would be imprisoned in the concentration camps at Sonnenburg , Brandenburg and finally , Oranienburg . 144 | On 2 February 1934 , Muhsam was transferred to the concentration camp at Oranienburg when finally on the night of 9 July 1934 , Muhsam was tortured and murdered by the guards , his battered corpse found hanging in a latrine the next morning . 145 | Spanish Revolution . 146 | In Spain , the national anarcho-syndicalist trade union Confederacion Nacional del Trabajo initially refused to join a popular front electoral alliance , and abstention by CNT supporters led to a right wing election victory . 147 | But in 1936 , the CNT changed its policy and anarchist votes helped bring the popular front back to power . 148 | Months later , the former ruling class responded with an attempted coup causing the Spanish Civil War ( 1936-1939 ) . 149 | In response to the army rebellion , an anarchist-inspired movement of peasants and workers , supported by armed militias , took control of Barcelona and of large areas of rural Spain where they collectivised the land . 150 | But even before the fascist victory in 1939 , the anarchists were losing ground in a bitter struggle with the Stalinists , who controlled the distribution of military aid to the Republican cause from the Soviet Union . 151 | The events known as the Spanish Revolution was a workers ' social revolution that began during the outbreak of the Spanish Civil War in 1936 and resulted in the widespread implementation of anarchist and more broadly libertarian socialist organizational principles throughout various portions of the country for two to three years , primarily Catalonia , Aragon , Andalusia , and parts of the Levante . 152 | Much of Spain 's economy was put under worker control ; in anarchist strongholds like Catalonia , the figure was as high as 75 % , but lower in areas with heavy Communist Party of Spain influence , as the Soviet-allied party actively resisted attempts at collectivization enactment . 153 | Factories were run through worker committees , agrarian areas became collectivised and run as libertarian communes . 154 | Anarchist historian Sam Dolgoff estimated that about eight million people participated directly or at least indirectly in the Spanish Revolution , which he claimed " came closer to realizing the ideal of the free stateless society on a vast scale than any other revolution in history . " 155 | Stalinist-led troops suppressed the collectives and persecuted both dissident Marxists and anarchists . 156 | The prominent Italian anarchist Camillo Berneri , who volunteered to fight against Franco was killed instead in Spain by gunmen associated with the Spanish Communist Party . 157 | Post-war years . 158 | Anarchism continued to influence important literary and intellectual personalities of the time , such as Albert Camus , Herbert Read , Paul Goodman , Dwight Macdonald , Allen Ginsberg , George Woodcock , Leopold Kohr , Julian Beck , John Cage and the French Surrealist group led by Andre Breton , which now openly embraced anarchism and collaborated in the Federation Anarchiste . 159 | Anarcho-pacifism became influential in the Anti-nuclear movement and anti war movements of the time as can be seen in the activism and writings of the English anarchist member of Campaign for Nuclear Disarmament Alex Comfort or the similar activism of the American catholic anarcho-pacifists Ammon Hennacy and Dorothy Day . 160 | Anarcho-pacifism became a " basis for a critique of militarism on both sides of the Cold War. " The resurgence of anarchist ideas during this period is well documented in Robert Graham 's , " Volume Two : The Emergence of the New Anarchism (1939-1977) " . 161 | Contemporary anarchism . 162 | In the United Kingdom in the 1970s this was associated with the punk rock movement , as exemplified by bands such as Crass and the Sex Pistols . 163 | The housing and employment crisis in most of Western Europe led to the formation of communes and squatter movements like that of Barcelona , Spain . 164 | In Denmark , squatters occupied a disused military base and declared the Freetown Christiania , an autonomous haven in central Copenhagen . 165 | Since the revival of anarchism in the mid 20th century , a number of new movements and schools of thought emerged . 166 | Although feminist tendencies have always been a part of the anarchist movement in the form of anarcha-feminism , they returned with vigour during the second wave of feminism in the 1960s . 167 | The American Civil Rights Movement and the movement against the war in Vietnam also contributed to the revival of North American anarchism . 168 | European anarchism of the late 20th century drew much of its strength from the labour movement , and both have incorporated animal rights activism . 169 | Anarchist anthropologist David Graeber and anarchist historian Andrej Grubacic have posited a rupture between generations of anarchism , with those " who often still have not shaken the sectarian habits " of the 19th century contrasted with the younger activists who are " much more informed , among other elements , by indigenous , feminist , ecological and cultural-critical ideas " , and who by the turn of the 21st century formed " by far the majority " of anarchists . 170 | Around the turn of the 21st century , anarchism grew in popularity and influence as part of the anti-war , anti-capitalist , and anti-globalisation movements . 171 | Anarchists became known for their involvement in protests against the meetings of the World Trade Organization ( WTO ) , Group of Eight , and the World Economic Forum . 172 | Some anarchist factions at these protests engaged in rioting , property destruction , and violent confrontations with police . 173 | These actions were precipitated by ad hoc , leaderless , anonymous cadres known as " black blocs " ; other organisational tactics pioneered in this time include security culture , affinity groups and the use of decentralised technologies such as the internet . 174 | A significant event of this period was the confrontations at WTO conference in Seattle in 1999 . 175 | According to anarchist scholar Simon Critchley , " contemporary anarchism can be seen as a powerful critique of the pseudo-libertarianism of contemporary neo-liberalism ... 176 | One might say that contemporary anarchism is about responsibility , whether sexual , ecological or socio-economic ; it flows from an experience of conscience about the manifold ways in which the West ravages the rest ; it is an ethical outrage at the yawning inequality , impoverishment and disenfranchisment that is so palpable locally and globally . " 177 | International anarchist federations in existence include the International of Anarchist Federations , the International Workers ' Association , and International Libertarian Solidarity . 178 | The largest organised anarchist movement today is in Spain , in the form of the Confederacion General del Trabajo ( CGT ) and the CNT . 179 | CGT membership was estimated at around 100,000 for 2003 . 180 | Other active syndicalist movements include in Sweden the Central Organisation of the Workers of Sweden and the Swedish Anarcho-syndicalist Youth Federation ; the CNT-AIT in France ; the Union Sindicale Italiana in Italy ; in the US Workers Solidarity Alliance and the UK Solidarity Federation . 181 | The revolutionary industrial unionist Industrial Workers of the World , claiming 2,000 paying members , and the International Workers Association , an anarcho-syndicalist successor to the First International , also remain active . 182 | Anarchist schools of thought . 183 | Anarchist schools of thought had been generally grouped in two main historical traditions , individualist anarchism and social anarchism , which have some different origins , values and evolution . 184 | The individualist wing of anarchism emphasises negative liberty , i.e. opposition to state or social control over the individual , while those in the social wing emphasise positive liberty to achieve one 's potential and argue that humans have needs that society ought to fulfill , " recognizing equality of entitlement " . 185 | In a chronological and theoretical sense , there are classical -- those created throughout the 19th century -- and post-classical anarchist schools -- those created since the mid-20th century and after . 186 | Beyond the specific factions of anarchist thought is philosophical anarchism , which embodies the theoretical stance that the state lacks moral legitimacy without accepting the imperative of revolution to eliminate it . 187 | A component especially of individualist anarchism philosophical anarchism may accept the existence of a minimal state as unfortunate , and usually temporary , " necessary evil " but argue that citizens do not have a moral obligation to obey the state when its laws conflict with individual autonomy . 188 | One reaction against sectarianism within the anarchist milieu was " anarchism without adjectives " , a call for toleration first adopted by Fernando Tarrida del Marmol in 1889 in response to the " bitter debates " of anarchist theory at the time . 189 | In abandoning the hyphenated anarchisms ( i.e. collectivist- , communist- , mutualist- and individualist-anarchism ) , it sought to emphasise the anti-authoritarian beliefs common to all anarchist schools of thought . 190 | Classical anarchist schools of thought . 191 | Mutualism . 192 | Mutualism began in 18th-century English and French labour movements before taking an anarchist form associated with Pierre-Joseph Proudhon in France and others in the United States . 193 | Proudhon proposed spontaneous order , whereby organization emerges without central authority , a " positive anarchy " where order arises when everybody does " what he wishes and only what he wishes " and where " business transactions alone produce the social order. " It is important to recognize that Proudhon distinguished between ideal political possibilities and practical governance . 194 | For this reason , much in contrast to some of his theoretical statements concerning ultimate spontaneous self-governance , Proudhon was heavily involved in French parliamentary politics and allied himself not with Anarchist but Socialist factions of workers movements and , in addition to advocating state-protected charters for worker-owned cooperatives , promoted certain nationalization schemes during his life of public service . 195 | Mutualist anarchism is concerned with reciprocity , free association , voluntary contract , federation , and credit and currency reform . 196 | According to the American mutualist William Batchelder Greene , each worker in the mutualist system would receive " just and exact pay for his work ; services equivalent in cost being exchangeable for services equivalent in cost , without profit or discount. " Mutualism has been retrospectively characterised as ideologically situated between individualist and collectivist forms of anarchism. " Blackwell Encyclopaedia of Political Thought " , Blackwell Publishing 1991 ISBN 0-631-17944-5 , p . 197 | 11 . 198 | Proudhon first characterised his goal as a " third form of society , the synthesis of communism and property . " 199 | Individualist anarchism . 200 | Individualist anarchism refers to several traditions of thought within the anarchist movement that emphasize the individual and their will over any kinds of external determinants such as groups , society , traditions , and ideological systems . 201 | Individualist anarchism is not a single philosophy but refers to a group of individualistic philosophies that sometimes are in conflict . 202 | In 1793 , William Godwin , who has often been cited as the first anarchist , wrote " Political Justice " , which some consider the first expression of anarchism . 203 | Godwin , a philosophical anarchist , from a rationalist and utilitarian basis opposed revolutionary action and saw a minimal state as a present " necessary evil " that would become increasingly irrelevant and powerless by the gradual spread of knowledge . 204 | Godwin advocated individualism , proposing that all cooperation in labour be eliminated on the premise that this would be most conducive with the general good . 205 | An influential form of individualist anarchism , called " egoism , " or egoist anarchism , was expounded by one of the earliest and best-known proponents of individualist anarchism , the German Max Stirner . 206 | Stirner 's " The Ego and Its Own " , published in 1844 , is a founding text of the philosophy . 207 | According to Stirner , the only limitation on the rights of the individual is their power to obtain what they desire , without regard for God , state , or morality . 208 | To Stirner , rights were " spooks " in the mind , and he held that society does not exist but " the individuals are its reality " . 209 | Stirner advocated self-assertion and foresaw unions of egoists , non-systematic associations continually renewed by all parties ' support through an act of will , which Stirner proposed as a form of organization in place of the state . 210 | Egoist anarchists argue that egoism will foster genuine and spontaneous union between individuals . 211 | " Egoism " has inspired many interpretations of Stirner 's philosophy . 212 | It was re-discovered and promoted by German philosophical anarchist and LGBT activist John Henry Mackay . 213 | Josiah Warren is widely regarded as the first American anarchist , and the four-page weekly paper he edited during 1833 , " The Peaceful Revolutionist " , was the first anarchist periodical published . 214 | For American anarchist historian Eunice Minette Schuster " It is apparent ... that Proudhonian Anarchism was to be found in the United States at least as early as 1848 and that it was not conscious of its affinity to the Individualist Anarchism of Josiah Warren and Stephen Pearl Andrews ... 215 | William B. Greene presented this Proudhonian Mutualism in its purest and most systematic form. " . 216 | Henry David Thoreau ( 1817-1862 ) was an important early influence in individualist anarchist thought in the United States and Europe . 217 | Thoreau was an American author , poet , naturalist , tax resister , development critic , surveyor , historian , philosopher , and leading transcendentalist . 218 | He is best known for his books " Walden " , a reflection upon simple living in natural surroundings , and his essay , " Civil Disobedience " , an argument for individual resistance to civil government in moral opposition to an unjust state . 219 | Later Benjamin Tucker fused Stirner 's egoism with the economics of Warren and Proudhon in his eclectic influential publication " Liberty " . 220 | From these early influences individualist anarchism in different countries attracted a small but diverse following of bohemian artists and intellectuals , free love and birth control advocates ( see Anarchism and issues related to love and sex ) , individualist naturists nudists ( see anarcho-naturism ) , freethought and anti-clearical activists as well as young anarchist outlaws in what became known as illegalism and individual reclamation ( see European individualist anarchism and individualist anarchism in France ) . 221 | These authors and activists included Oscar Wilde , Emile Armand , Han Ryner , Henri Zisly , Renzo Novatore , Miguel Gimenez Igualada , Adolf Brand and Lev Chernyi among others . 222 | Social anarchism . 223 | Social anarchism calls for a system with common ownership of means of production and democratic control of all organizations , without any government authority or coercion . 224 | It is the largest school of thought in anarchism . 225 | Social anarchism rejects private property , seeing it as a source of social inequality ( while retaining respect for personal property ) , and emphasises cooperation and mutual aid . 226 | Collectivist anarchism . 227 | Collectivist anarchism , also referred to as " revolutionary socialism " or a form of such , is a revolutionary form of anarchism , commonly associated with Mikhail Bakunin and Johann Most . 228 | Collectivist anarchists oppose all private ownership of the means of production , instead advocating that ownership be collectivised . 229 | This was to be achieved through violent revolution , first starting with a small cohesive group through acts of violence , or " propaganda by the deed " , which would inspire the workers as a whole to revolt and forcibly collectivise the means of production . 230 | However , collectivization was not to be extended to the distribution of income , as workers would be paid according to time worked , rather than receiving goods being distributed " according to need " as in anarcho-communism . 231 | This position was criticised by anarchist communists as effectively " uphold the wages system " . 232 | Collectivist anarchism arose contemporaneously with Marxism but opposed the Marxist dictatorship of the proletariat , despite the stated Marxist goal of a collectivist stateless society . 233 | Anarchist , communist and collectivist ideas are not mutually exclusive ; although the collectivist anarchists advocated compensation for labour , some held out the possibility of a post-revolutionary transition to a communist system of distribution according to need . 234 | Anarcho-communism . 235 | Anarchist communism ( also known as anarcho-communism , libertarian communism and occasionally as free communism ) is a theory of anarchism that advocates abolition of the state , markets , money , private property ( while retaining respect for personal property ) , and capitalism in favor of common ownership of the means of production , direct democracy and a horizontal network of voluntary associations and workers ' councils with production and consumption based on the guiding principle : " from each according to his ability , to each according to his need " . 236 | Some forms of anarchist communism such as insurrectionary anarchism are strongly influenced by egoism and radical individualism , believing anarcho-communism is the best social system for the realization of individual freedom . 237 | Most anarcho-communists view anarcho-communism as a way of reconciling the opposition between the individual and society . 238 | Anarcho-communism developed out of radical socialist currents after the French revolution but was first formulated as such in the Italian section of the First International . 239 | The theoretical work of Peter Kropotkin took importance later as it expanded and developed pro-organizationalist and insurrectionary anti-organizationalist sections . 240 | To date , the best known examples of an anarchist communist society ( i.e. , established around the ideas as they exist today and achieving worldwide attention and knowledge in the historical canon ) , are the anarchist territories during the Spanish Revolution and the Free Territory during the Russian Revolution . 241 | Through the efforts and influence of the Spanish Anarchists during the Spanish Revolution within the Spanish Civil War , starting in 1936 anarchist communism existed in most of Aragon , parts of the Levante and Andalusia , as well as in the stronghold of Anarchist Catalonia before being crushed by the combined forces of the regime that won the war , Hitler , Mussolini , Spanish Communist Party repression ( backed by the USSR ) as well as economic and armaments blockades from the capitalist countries and the Spanish Republic itself . 242 | During the Russian Revolution , anarchists such as Nestor Makhno worked to create and defend -- through the Revolutionary Insurrectionary Army of Ukraine -- anarchist communism in the Free Territory of the Ukraine from 1919 before being conquered by the Bolsheviks in 1921 . 243 | Anarcho-syndicalism . 244 | Anarcho-syndicalism is a branch of anarchism that focuses on the labor movement . 245 | Anarcho-syndicalists view labor unions as a potential force for revolutionary social change , replacing capitalism and the state with a new society democratically self-managed by workers . 246 | The basic principles of anarcho-syndicalism are : Workers ' , Direct action and Workers ' self-management 247 | Anarcho-syndicalists believe that only direct action -- that is , action concentrated on directly attaining a goal , as opposed to indirect action , such as electing a representative to a government position -- will allow workers to liberate themselves . 248 | Moreover , anarcho-syndicalists believe that workers ' organizations ( the organizations that struggle against the wage system , which , in anarcho-syndicalist theory , will eventually form the basis of a new society ) should be self-managing . 249 | They should not have bosses or " business agents " ; rather , the workers should be able to make all the decisions that affect them themselves . 250 | Rudolf Rocker was one of the most popular voices in the anarcho-syndicalist movement . 251 | He outlined a view of the origins of the movement , what it sought , and why it was important to the future of labor in his 1938 pamphlet " Anarcho-Syndicalism " .The International Workers Association is an international anarcho-syndicalist federation of various labor unions from different countries . 252 | The Spanish Confederacion Nacional del Trabajo played and still plays a major role in the Spanish labor movement . 253 | It was also an important force in the Spanish Civil War . 254 | Post-classical schools of thought . 255 | Anarchism continues to generate many philosophies and movements , at times eclectic , drawing upon various sources , and syncretic , combining disparate concepts to create new philosophical approaches . 256 | Green anarchism ( or eco-anarchism ) is a school of thought within anarchism that emphasizes environmental issues , with an important precedent in anarcho-naturism , and whose main contemporary currents are anarcho-primitivism and social ecology . 257 | Anarcha-feminism ( also called anarchist feminism and anarcho-feminism ) combines anarchism with feminism . 258 | It generally views patriarchy as a manifestation of involuntary coercive hierarchy that should be replaced by decentralized free association . 259 | Anarcha-feminists believe that the struggle against patriarchy is an essential part of class struggle , and the anarchist struggle against the state . 260 | In essence , the philosophy sees anarchist struggle as a necessary component of feminist struggle and vice-versa . 261 | L . 262 | Susan Brown claims that " as anarchism is a political philosophy that opposes all relationships of power , it is inherently feminist " . 263 | Anarcha-feminism began with the late 19th century writings of early feminist anarchists such as Emma Goldman and Voltairine de Cleyre . 264 | Anarcho-pacifism is a tendency that rejects violence in the struggle for social change ( see non-violence ) . 265 | It developed " mostly in the Netherlands , Britain , and the United States , before and during the Second World War " . 266 | Christian anarchism is a movement in political theology that combines anarchism and Christianity . 267 | Its main proponents included Leo Tolstoy , Dorothy Day , Ammon Hennacy , and Jacques Ellul . 268 | Platformism is a tendency within the wider anarchist movement based on the organisational theories in the tradition of Dielo Truda 's " Organizational Platform of the General Union of Anarchists (Draft) " . 269 | The document was based on the experiences of Russian anarchists in the 1917 October Revolution , which led eventually to the victory of the Bolsheviks over the anarchists and other groups . 270 | The " Platform " attempted to address and explain the anarchist movement 's failures during the Russian Revolution . 271 | Synthesis anarchism is a form of anarchist organization that tries to join anarchists of different tendencies under the principles of anarchism without adjectives . 272 | In the 1920s , this form found as its main proponents the anarcho-communists Voline and Sebastien Faure . 273 | It is the main principle behind the anarchist federations grouped around the contemporary global International of Anarchist Federations . 274 | Post-left anarchy is a recent current in anarchist thought that promotes a critique of anarchism 's relationship to traditional Left-wing politics . 275 | Some post-leftists seek to escape the confines of ideology in general also presenting a critique of organizations and morality . 276 | Influenced by the work of Max Stirner and by the Marxist Situationist International , post-left anarchy is marked by a focus on social insurrection and a rejection of leftist social organisation . 277 | Insurrectionary anarchism is a revolutionary theory , practice , and tendency within the anarchist movement which emphasizes insurrection within anarchist practice . 278 | It is critical of formal organizations such as labor unions and federations that are based on a political programme and periodic congresses . 279 | Instead , insurrectionary anarchists advocate informal organization and small affinity group based organization . 280 | Insurrectionary anarchists put value in attack , permanent class conflict , and a refusal to negotiate or compromise with class enemies . 281 | Post-anarchism is a theoretical move towards a synthesis of classical anarchist theory and poststructuralist thought , drawing from diverse ideas including post-modernism , autonomist marxism , post-left anarchy , situationism , and postcolonialism . 282 | Anarcho-capitalism advocates the elimination of the state in favor of individual sovereignty in a free market . 283 | Anarcho-capitalism developed from radical anti-state libertarianism and individualist anarchism , There is a strong current within anarchism which does not consider that anarcho-capitalism can be considered a part of the anarchist movement due to the fact that anarchism has historically been an anti-capitalist movement and for definitional reasons which see anarchism incompatible with capitalist forms . 284 | Internal issues and debates . 285 | Anarchism is a philosophy that embodies many diverse attitudes , tendencies and schools of thought ; as such , disagreement over questions of values , ideology and tactics is common . 286 | The compatibility of capitalism , nationalism , and religion with anarchism is widely disputed . 287 | Similarly , anarchism enjoys complex relationships with ideologies such as Marxism , communism and capitalism . 288 | Anarchists may be motivated by humanism , divine authority , enlightened self-interest , veganism or any number of alternative ethical doctrines . 289 | Phenomena such as civilization , technology ( e.g. within anarcho-primitivism and insurrectionary anarchism ) , and the democratic process may be sharply criticized within some anarchist tendencies and simultaneously lauded in others . 290 | On a tactical level , while propaganda of the deed was a tactic used by anarchists in the 19th century ( e.g. the Nihilist movement ) , some contemporary anarchists espouse alternative direct action methods such as nonviolence , counter-economics and anti-state cryptography to bring about an anarchist society . 291 | About the scope of an anarchist society , some anarchists advocate a global one , while others do so by local ones . 292 | The diversity in anarchism has led to widely different use of identical terms among different anarchist traditions , which has led to many definitional concerns in anarchist theory . 293 | Topics of interest . 294 | Intersecting and overlapping between various schools of thought , certain topics of interest and internal disputes have proven perennial within anarchist theory . 295 | Free love . 296 | An important current within anarchism is free love . 297 | Free love advocates sometimes traced their roots back to Josiah Warren and to experimental communities , viewed sexual freedom as a clear , direct expression of an individual 's self-ownership . 298 | Free love particularly stressed women 's rights since most sexual laws discriminated against women : for example , marriage laws and anti-birth control measures . 299 | The most important American free love journal was " Lucifer the Lightbearer " ( 1883-1907 ) edited by Moses Harman and Lois Waisbrooker , but also there existed Ezra Heywood and Angela Heywood 's " The Word " ( 1872-1890 , 1892-1893 ) . 300 | " Free Society " ( 1895-1897 as " The Firebrand " ; 1897-1904 as " Free Society " ) was a major anarchist newspaper in the United States at the end of the 19th and beginning of the 20th centuries . 301 | The publication advocated free love and women 's rights , and critiqued " Comstockery " -- censorship of sexual information . 302 | Also M . 303 | E . 304 | Lazarus was an important American individualist anarchist who promoted free love . 305 | In New York City 's Greenwich Village , bohemian feminists and socialists advocated self-realisation and pleasure for women ( and also men ) in the here and now . 306 | They encouraged playing with sexual roles and sexuality , and the openly bisexual radical Edna St . 307 | Vincent Millay and the lesbian anarchist Margaret Anderson were prominent among them . 308 | Discussion groups organised by the Villagers were frequented by Emma Goldman , among others . 309 | Magnus Hirschfeld noted in 1923 that Goldman " has campaigned boldly and steadfastly for individual rights , and especially for those deprived of their rights . 310 | Thus it came about that she was the first and only woman , indeed the first and only American , to take up the defense of homosexual love before the general public. " In fact , before Goldman , heterosexual anarchist Robert Reitzel ( 1849-1898 ) spoke positively of homosexuality from the beginning of the 1890s in his Detroit-based German language journal " Der arme Teufel " . 311 | In Argentina anarcha-feminist Virginia Bolten published the newspaper called " " ( ) , which was published nine times in Rosario between 8 January 1896 and 1 January 1897 , and was revived , briefly , in 1901 . 312 | In Europe the main propagandist of free love within individualist anarchism was Emile Armand . 313 | He proposed the concept of " la camaraderie amoureuse " to speak of free love as the possibility of voluntary sexual encounter between consenting adults . 314 | He was also a consistent proponent of polyamory . 315 | In Germany the stirnerists Adolf Brand and John Henry Mackay were pioneering campaigners for the acceptance of male bisexuality and homosexuality . 316 | Mujeres Libres was an anarchist women 's organization in Spain that aimed to empower working class women . 317 | It was founded in 1936 by Lucia Sanchez Saornil , Mercedes Comaposada and Amparo Poch y Gascon and had approximately 30,000 members . 318 | The organization was based on the idea of a " double struggle " for women 's liberation and social revolution and argued that the two objectives were equally important and should be pursued in parallel . 319 | In order to gain mutual support , they created networks of women anarchists . 320 | Lucia Sanchez Saornil was a main founder of the Spanish anarcha-feminist federation Mujeres Libres who was open about her lesbianism . 321 | She was published in a variety of literary journals where working under a male pen name , she was able to explore lesbian themes at a time when homosexuality was criminalized and subject to censorship and punishment . 322 | More recently , the British anarcho-pacifist Alex Comfort gained notoriety during the sexual revolution for writing the bestseller sex manual " The Joy of Sex " . 323 | The issue of free love has a dedicated treatment in the work of French anarcho-hedonist philosopher Michel Onfray in such works as " Theorie du corps amoureux : pour une erotique solaire " ( 2000 ) and " L'invention du plaisir : fragments cyreaniques " ( 2002 ) . 324 | Libertarian education and freethought . 325 | In the United States " freethought was a basically anti-christian , anti-clerical movement , whose purpose was to make the individual politically and spiritually free to decide for himself on religious matters . 326 | A number of contributors to " Liberty " ( anarchist publication ) were prominent figures in both freethought and anarchism . 327 | The individualist anarchist George MacDonald was a co-editor of " Freethought " and , for a time , " The Truth Seeker " . 328 | E.C . 329 | Walker was co-editor of the excellent free-thought / free love journal " Lucifer , the Light-Bearer " " . 330 | " Many of the anarchists were ardent freethinkers ; reprints from freethought papers such as " Lucifer , the Light-Bearer " , " Freethought " and " The Truth Seeker " appeared in " Liberty " ... 331 | The church was viewed as a common ally of the state and as a repressive force in and of itself " . 332 | In 1901 , Catalan anarchist and free-thinker Francesc Ferrer i Guardia established " modern " or progressive schools in Barcelona in defiance of an educational system controlled by the Catholic Church . 333 | The schools ' stated goal was to " educate the working class in a rational , secular and non-coercive setting " . 334 | Fiercely anti-clerical , Ferrer believed in " freedom in education " , education free from the authority of church and state . 335 | Murray Bookchin wrote : " This period was the heyday of libertarian schools and pedagogical projects in all areas of the country where Anarchists exercised some degree of influence . 336 | Perhaps the best-known effort in this field was Francisco Ferrer 's Modern School ( Escuela Moderna ) , a project which exercised a considerable influence on Catalan education and on experimental techniques of teaching generally. " La Escuela Moderna , and Ferrer 's ideas generally , formed the inspiration for a series of " Modern Schools " in the United States , Cuba , South America and London . 337 | The first of these was started in New York City in 1911 . 338 | It also inspired the Italian newspaper " Universita popolare " , founded in 1901 . 339 | Russian christian anarchist Leo Tolstoy established a school for peasant children on his estate . 340 | Tolstoy 's educational experiments were short-lived due to harassment by the Tsarist secret police . 341 | Tolstoy established a conceptual difference between education and culture . 342 | He thought that " Education is the tendency of one man to make another just like himself ... 343 | Education is culture under restraint , culture is free . 344 | is when the teaching is forced upon the pupil , and when then instruction is exclusive , that is when only those subjects are taught which the educator regards as necessary " . 345 | For him " without compulsion , education was transformed into culture " . 346 | A more recent libertarian tradition on education is that of unschooling and the free school in which child-led activity replaces pedagogic approaches . 347 | Experiments in Germany led to A . 348 | S . 349 | Neill founding what became Summerhill School in 1921 . 350 | Summerhill is often cited as an example of anarchism in practice . 351 | However , although Summerhill and other free schools are radically libertarian , they differ in principle from those of Ferrer by not advocating an overtly political class struggle-approach . 352 | In addition to organizing schools according to libertarian principles , anarchists have also questioned the concept of schooling per se . 353 | The term deschooling was popularized by Ivan Illich , who argued that the school as an institution is dysfunctional for self-determined learning and serves the creation of a consumer society instead . 354 | Criticisms . 355 | Criticisms of anarchism include moral criticisms and pragmatic criticisms . 356 | Anarchism is often evaluated as unfeasible or utopian by its critics . 357 | European history professor Carl Landauer , in his book " European Socialism " argued that social anarchism is unrealistic and that government is a " lesser evil " than a society without " repressive force. " He also argued that " ill intentions will cease if repressive force disappears " is an " absurdity. " The anarchist tendency known as platformism has been criticized by Situationists , insurrectionaries , synthesis anarchists , and others of preserving tacitly statist , authoritarian or bureaucratic tendencies . 358 | Further reading . 359 | Film . 360 | See List of films dealing with Anarchism 361 | Autism 362 | Autism is a disorder of neural development characterized by impaired social interaction and verbal and non-verbal communication , and by restricted , repetitive or stereotyped behavior . 363 | The diagnostic criteria require that symptoms become apparent before a child is three years old . 364 | Autism affects information processing in the brain by altering how nerve cells and their synapses connect and organize ; how this occurs is not well understood . 365 | It is one of three recognized disorders in the autism spectrum ( ASDs ) , the other two being Asperger syndrome , which lacks delays in cognitive development and language , and pervasive developmental disorder , not otherwise specified ( commonly abbreviated as PDD-NOS ) , which is diagnosed when the full set of criteria for autism or Asperger syndrome are not met . 366 | Autism has a strong genetic basis , although the genetics of autism are complex and it is unclear whether ASD is explained more by rare mutations , or by rare combinations of common genetic variants . 367 | In rare cases , autism is strongly associated with agents that cause birth defects . 368 | Controversies surround other proposed environmental causes , such as heavy metals , pesticides or childhood vaccines ; the vaccine hypotheses are biologically implausible and lack convincing scientific evidence . 369 | The prevalence of autism is about 1-2 per 1,000 people worldwide , and it occurs about four times more often in boys than girls . 370 | The Centers for Disease Control and Prevention ( CDC ) report 20 per 1,000 children in the United States are diagnosed with ASD , up from 11 per 1,000 in 2008 . 371 | The number of people diagnosed with autism has been increasing dramatically since the 1980s , partly due to changes in diagnostic practice and government-subsidized financial incentives for named diagnoses ; the question of whether actual prevalence has increased is unresolved . 372 | Parents usually notice signs in the first two years of their child 's life . 373 | The signs usually develop gradually , but some autistic children first develop more normally and then regress . 374 | Early behavioral , cognitive , or speech interventions can help autistic children gain self-care , social , and communication skills . 375 | Although there is no known cure , there have been reported cases of children who recovered . 376 | Not many children with autism live independently after reaching adulthood , though some become successful . 377 | An autistic culture has developed , with some individuals seeking a cure and others believing autism should be accepted as a difference and not treated as a disorder . 378 | Characteristics . 379 | Autism is a highly variable neurodevelopmental disorder that first appears during infancy or childhood , and generally follows a steady course without remission . 380 | Overt symptoms gradually begin after the age of six months , become established by age two or three years , and tend to continue through adulthood , although often in more muted form . 381 | It is distinguished not by a single symptom , but by a characteristic triad of symptoms : impairments in social interaction ; impairments in communication ; and restricted interests and repetitive behavior . 382 | Other aspects , such as atypical eating , are also common but are not essential for diagnosis . 383 | Autism 's individual symptoms occur in the general population and appear not to associate highly , without a sharp line separating pathologically severe from common traits . 384 | Social development . 385 | Social deficits distinguish autism and the related autism spectrum disorders ( ASD ; see Classification ) from other developmental disorders . 386 | People with autism have social impairments and often lack the intuition about others that many people take for granted . 387 | Noted autistic Temple Grandin described her inability to understand the social communication of neurotypicals , or people with normal neural development , as leaving her feeling " like an anthropologist on Mars " . 388 | Unusual social development becomes apparent early in childhood . 389 | Autistic infants show less attention to social stimuli , smile and look at others less often , and respond less to their own name . 390 | Autistic toddlers differ more strikingly from social norms ; for example , they have less eye contact and turn taking , and do not have the ability to use simple movements to express themselves , such as the deficiency to point at things . 391 | Three- to five-year-old autistic children are less likely to exhibit social understanding , approach others spontaneously , imitate and respond to emotions , communicate nonverbally , and take turns with others . 392 | However , they do form attachments to their primary caregivers . 393 | Most autistic children display moderately less attachment security than non-autistic children , although this difference disappears in children with higher mental development or less severe ASD . 394 | Older children and adults with ASD perform worse on tests of face and emotion recognition . 395 | Children with high-functioning autism suffer from more intense and frequent loneliness compared to non-autistic peers , despite the common belief that children with autism prefer to be alone . 396 | Making and maintaining friendships often proves to be difficult for those with autism . 397 | For them , the quality of friendships , not the number of friends , predicts how lonely they feel . 398 | Functional friendships , such as those resulting in invitations to parties , may affect the quality of life more deeply . 399 | There are many anecdotal reports , but few systematic studies , of aggression and violence in individuals with ASD . 400 | The limited data suggest that , in children with intellectual disability , autism is associated with aggression , destruction of property , and tantrums . 401 | A 2007 study interviewed parents of 67 children with ASD and reported that about two-thirds of the children had periods of severe tantrums and about one-third had a history of aggression , with tantrums significantly more common than in non-autistic children with language impairments . 402 | A 2008 Swedish study found that , of individuals aged 15 or older discharged from hospital with a diagnosis of ASD , those who committed violent crimes were significantly more likely to have other psychopathological conditions such as psychosis . 403 | Communication . 404 | About a third to a half of individuals with autism do not develop enough natural speech to meet their daily communication needs . 405 | Differences in communication may be present from the first year of life , and may include delayed onset of babbling , unusual gestures , diminished responsiveness , and vocal patterns that are not synchronized with the caregiver . 406 | In the second and third years , autistic children have less frequent and less diverse babbling , consonants , words , and word combinations ; their gestures are less often integrated with words . 407 | Autistic children are less likely to make requests or share experiences , and are more likely to simply repeat others ' words ( echolalia ) or reverse pronouns . 408 | Joint attention seems to be necessary for functional speech , and deficits in joint attention seem to distinguish infants with ASD : for example , they may look at a pointing hand instead of the pointed-at object , and they consistently fail to point at objects in order to comment on or share an experience . 409 | Autistic children may have difficulty with imaginative play and with developing symbols into language . 410 | In a pair of studies , high-functioning autistic children aged 8-15 performed equally well as , and adults better than , individually matched controls at basic language tasks involving vocabulary and spelling . 411 | Both autistic groups performed worse than controls at complex language tasks such as figurative language , comprehension and inference . 412 | As people are often sized up initially from their basic language skills , these studies suggest that people speaking to autistic individuals are more likely to overestimate what their audience comprehends . 413 | Repetitive behavior . 414 | Autistic individuals display many forms of repetitive or restricted behavior , which the Repetitive Behavior Scale-Revised ( RBS-R ) categorizes as follows . 415 | No single repetitive or self-injurious behavior seems to be specific to autism , but only autism appears to have an elevated pattern of occurrence and severity of these behaviors . 416 | Other symptoms . 417 | Autistic individuals may have symptoms that are independent of the diagnosis , but that can affect the individual or the family . 418 | An estimated 0.5 % to 10 % of individuals with ASD show unusual abilities , ranging from splinter skills such as the memorization of trivia to the extraordinarily rare talents of prodigious autistic savants . 419 | Many individuals with ASD show superior skills in perception and attention , relative to the general population . 420 | Sensory abnormalities are found in over 90 % of those with autism , and are considered core features by some , although there is no good evidence that sensory symptoms differentiate autism from other developmental disorders . 421 | Differences are greater for under-responsivity ( for example , walking into things ) than for over-responsivity ( for example , distress from loud noises ) or for sensation seeking ( for example , rhythmic movements ) . 422 | An estimated 60 % -80 % of autistic people have motor signs that include poor muscle tone , poor motor planning , and toe walking ; deficits in motor coordination are pervasive across ASD and are greater in autism proper . 423 | Unusual eating behavior occurs in about three-quarters of children with ASD , to the extent that it was formerly a diagnostic indicator . 424 | Selectivity is the most common problem , although eating rituals and food refusal also occur ; this does not appear to result in malnutrition . 425 | Although some children with autism also have gastrointestinal ( GI ) symptoms , there is a lack of published rigorous data to support the theory that autistic children have more or different GI symptoms than usual ; studies report conflicting results , and the relationship between GI problems and ASD is unclear . 426 | Parents of children with ASD have higher levels of stress . 427 | Siblings of children with ASD report greater admiration of and less conflict with the affected sibling than siblings of unaffected children and were similar to siblings of children with Down syndrome in these aspects of the sibling relationship . 428 | However , they reported lower levels of closeness and intimacy than siblings of children with Down syndrome ; siblings of individuals with ASD have greater risk of negative well-being and poorer sibling relationships as adults . 429 | Causes . 430 | It has long been presumed that there is a common cause at the genetic , cognitive , and neural levels for autism 's characteristic triad of symptoms . 431 | However , there is increasing suspicion that autism is instead a complex disorder whose core aspects have distinct causes that often co-occur . 432 | Autism has a strong genetic basis , although the genetics of autism are complex and it is unclear whether ASD is explained more by rare mutations with major effects , or by rare multigene interactions of common genetic variants . 433 | Complexity arises due to interactions among multiple genes , the environment , and epigenetic factors which do not change DNA but are heritable and influence gene expression . 434 | Studies of twins suggest that heritability is 0.7 for autism and as high as 0.9 for ASD , and siblings of those with autism are about 25 times more likely to be autistic than the general population . 435 | However , most of the mutations that increase autism risk have not been identified . 436 | Typically , autism can not be traced to a Mendelian ( single-gene ) mutation or to a single chromosome abnormality , and none of the genetic syndromes associated with ASDs have been shown to selectively cause ASD . 437 | Numerous candidate genes have been located , with only small effects attributable to any particular gene . 438 | The large number of autistic individuals with unaffected family members may result from copy number variations -- spontaneous deletions or duplications in genetic material during meiosis . 439 | Hence , a substantial fraction of autism cases may be traceable to genetic causes that are highly heritable but not inherited : that is , the mutation that causes the autism is not present in the parental genome . 440 | Several lines of evidence point to synaptic dysfunction as a cause of autism . 441 | Some rare mutations may lead to autism by disrupting some synaptic pathways , such as those involved with cell adhesion . 442 | Gene replacement studies in mice suggest that autistic symptoms are closely related to later developmental steps that depend on activity in synapses and on activity-dependent changes . 443 | All known teratogens ( agents that cause birth defects ) related to the risk of autism appear to act during the first eight weeks from conception , and though this does not exclude the possibility that autism can be initiated or affected later , it is strong evidence that autism arises very early in development . 444 | Although evidence for other environmental causes is anecdotal and has not been confirmed by reliable studies , extensive searches are underway . 445 | Environmental factors that have been claimed to contribute to or exacerbate autism , or may be important in future research , include certain foods , infectious disease , heavy metals , solvents , diesel exhaust , PCBs , phthalates and phenols used in plastic products , pesticides , brominated flame retardants , alcohol , smoking , illicit drugs , vaccines , and prenatal stress , although no links have been found , and some have been completely disproven . 446 | Parents may first become aware of autistic symptoms in their child around the time of a routine vaccination . 447 | This has led to unsupported theories blaming vaccine " overload " , a vaccine preservative , or the MMR vaccine for causing autism . 448 | The latter theory was supported by a litigation-funded study that has since been shown to have been " an elaborate fraud " . 449 | Although these theories lack convincing scientific evidence and are biologically implausible , parental concern about a potential vaccine link with autism has led to lower rates of childhood immunizations , outbreaks of previously controlled childhood diseases in some countries , and the preventable deaths of several children . 450 | Mechanism . 451 | Autism 's symptoms result from maturation-related changes in various systems of the brain . 452 | How autism occurs is not well understood . 453 | Its mechanism can be divided into two areas : the pathophysiology of brain structures and processes associated with autism , and the neuropsychological linkages between brain structures and behaviors . 454 | The behaviors appear to have multiple pathophysiologies . 455 | Pathophysiology . 456 | Unlike many other brain disorders , such as Parkinson 's , autism does not have a clear unifying mechanism at either the molecular , cellular , or systems level ; it is not known whether autism is a few disorders caused by mutations converging on a few common molecular pathways , or is ( like intellectual disability ) a large set of disorders with diverse mechanisms . 457 | Autism appears to result from developmental factors that affect many or all functional brain systems , and to disturb the timing of brain development more than the final product . 458 | Neuroanatomical studies and the associations with teratogens strongly suggest that autism 's mechanism includes alteration of brain development soon after conception . 459 | This anomaly appears to start a cascade of pathological events in the brain that are significantly influenced by environmental factors . 460 | Just after birth , the brains of autistic children tend to grow faster than usual , followed by normal or relatively slower growth in childhood . 461 | It is not known whether early overgrowth occurs in all autistic children . 462 | It seems to be most prominent in brain areas underlying the development of higher cognitive specialization . 463 | Hypotheses for the cellular and molecular bases of pathological early overgrowth include the following : 464 | Interactions between the immune system and the nervous system begin early during the embryonic stage of life , and successful neurodevelopment depends on a balanced immune response . 465 | Aberrant immune activity during critical periods of neurodevelopment is possibly part of the mechanism of some forms of ASD . 466 | Although some abnormalities in the immune system have been found in specific subgroups of autistic individuals , it is not known whether these abnormalities are relevant to or secondary to autism 's disease processes . 467 | As autoantibodies are found in conditions other than ASD , and are not always present in ASD , the relationship between immune disturbances and autism remains unclear and controversial . 468 | The relationship of neurochemicals to autism is not well understood ; several have been investigated , with the most evidence for the role of serotonin and of genetic differences in its transport . 469 | The role of group I metabotropic glutamate receptors ( mGluR ) in the pathogenesis of fragile X syndrome , the most common identified genetic cause of autism , has led to interest in the possible implications for future autism research into this pathway . 470 | Some data suggest an increase in several growth hormones ; other data argue for diminished growth factors . 471 | Also , some inborn errors of metabolism are associated with autism , but probably account for less than 5 % of cases . 472 | The mirror neuron system ( MNS ) theory of autism hypothesizes that distortion in the development of the MNS interferes with imitation and leads to autism 's core features of social impairment and communication difficulties . 473 | The MNS operates when an animal performs an action or observes another animal perform the same action . 474 | The MNS may contribute to an individual 's understanding of other people by enabling the modeling of their behavior via embodied simulation of their actions , intentions , and emotions . 475 | Several studies have tested this hypothesis by demonstrating structural abnormalities in MNS regions of individuals with ASD , delay in the activation in the core circuit for imitation in individuals with Asperger syndrome , and a correlation between reduced MNS activity and severity of the syndrome in children with ASD . 476 | However , individuals with autism also have abnormal brain activation in many circuits outside the MNS and the MNS theory does not explain the normal performance of autistic children on imitation tasks that involve a goal or object . 477 | ASD-related patterns of low function and aberrant activation in the brain differ depending on whether the brain is doing social or nonsocial tasks . 478 | In autism there is evidence for reduced functional connectivity of the default network , a large-scale brain network involved in social and emotional processing , with intact connectivity of the task-positive network , used in sustained attention and goal-directed thinking . 479 | In people with autism the two networks are not negatively correlated in time , suggesting an imbalance in toggling between the two networks , possibly reflecting a disturbance of self-referential thought . 480 | A 2008 brain-imaging study found a specific pattern of signals in the cingulate cortex which differs in individuals with ASD . 481 | The underconnectivity theory of autism hypothesizes that autism is marked by underfunctioning high-level neural connections and synchronization , along with an excess of low-level processes . 482 | Evidence for this theory has been found in functional neuroimaging studies on autistic individuals and by a brainwave study that suggested that adults with ASD have local overconnectivity in the cortex and weak functional connections between the frontal lobe and the rest of the cortex . 483 | Other evidence suggests the underconnectivity is mainly within each hemisphere of the cortex and that autism is a disorder of the association cortex . 484 | From studies based on event-related potentials , transient changes to the brain 's electrical activity in response to stimuli , there is considerable evidence for differences in autistic individuals with respect to attention , orientiation to auditory and visual stimuli , novelty detection , language and face processing , and information storage ; several studies have found a preference for nonsocial stimuli . 485 | For example , magnetoencephalography studies have found evidence in autistic children of delayed responses in the brain 's processing of auditory signals . 486 | In the genetic area , relations have been found between autism and schizophrenia based on duplications and deletions of chromosomes ; research showed that schizophrenia and autism are significantly more common in combination with 1q21.1 deletion syndrome . 487 | Research on autism/schizophrenia relations for chromosome 15 ( 15q13.3 ) , chromosome 16 ( 16p13.1 ) and chromosome 17 ( 17p12 ) are inconclusive . 488 | Neuropsychology . 489 | Two major categories of cognitive theories have been proposed about the links between autistic brains and behavior . 490 | The first category focuses on deficits in social cognition . 491 | Simon Baron-Cohen 's empathizing-systemizing theory postulates that autistic individuals can systemize -- that is , they can develop internal rules of operation to handle events inside the brain -- but are less effective at empathizing by handling events generated by other agents . 492 | An extension , the extreme male brain theory , hypothesizes that autism is an extreme case of the male brain , defined psychometrically as individuals in whom systemizing is better than empathizing . 493 | These theories are somewhat related to Baron-Cohen 's earlier theory of mind approach , which hypothesizes that autistic behavior arises from an inability to ascribe mental states to oneself and others . 494 | The theory of mind hypothesis is supported by autistic children 's atypical responses to the Sally-Anne test for reasoning about others ' motivations , and the mirror neuron system theory of autism described in " Pathophysiology " maps well to the hypothesis . 495 | However , most studies have found no evidence of impairment in autistic individuals ' ability to understand other people 's basic intentions or goals ; instead , data suggests that impairments are found in understanding more complex social emotions or in considering others ' viewpoints . 496 | The second category focuses on nonsocial or general processing : the executive functions such as working memory , planning , inhibition . 497 | In his review , Kenworthy states that " the claim of executive dysfunction as a causal factor in autism is controversial " , however , " it is clear that executive dysfunction plays a role in the social and cognitive deficits observed in individuals with autism " . 498 | Tests of core executive processes such as eye movement tasks indicate improvement from late childhood to adolescence , but performance never reaches typical adult levels . 499 | A strength of the theory is predicting stereotyped behavior and narrow interests ; two weaknesses are that executive function is hard to measure and that executive function deficits have not been found in young autistic children . 500 | Weak central coherence theory hypothesizes that a limited ability to see the big picture underlies the central disturbance in autism . 501 | One strength of this theory is predicting special talents and peaks in performance in autistic people . 502 | A related theory -- enhanced perceptual functioning -- focuses more on the superiority of locally oriented and perceptual operations in autistic individuals . 503 | These theories map well from the underconnectivity theory of autism . 504 | Neither category is satisfactory on its own ; social cognition theories poorly address autism 's rigid and repetitive behaviors , while the nonsocial theories have difficulty explaining social impairment and communication difficulties . 505 | A combined theory based on multiple deficits may prove to be more useful . 506 | Diagnosis . 507 | Diagnosis is based on behavior , not cause or mechanism . 508 | Autism is defined in the DSM-IV-TR as exhibiting at least six symptoms total , including at least two symptoms of qualitative impairment in social interaction , at least one symptom of qualitative impairment in communication , and at least one symptom of restricted and repetitive behavior . 509 | Sample symptoms include lack of social or emotional reciprocity , stereotyped and repetitive use of language or idiosyncratic language , and persistent preoccupation with parts of objects . 510 | Onset must be prior to age three years , with delays or abnormal functioning in either social interaction , language as used in social communication , or symbolic or imaginative play . 511 | The disturbance must not be better accounted for by Rett syndrome or childhood disintegrative disorder . 512 | ICD-10 uses essentially the same definition . 513 | Several diagnostic instruments are available . 514 | Two are commonly used in autism research : the Autism Diagnostic Interview-Revised ( ADI-R ) is a semistructured parent interview , and the Autism Diagnostic Observation Schedule(ADOS) uses observation and interaction with the child . 515 | The Childhood Autism Rating Scale ( CARS ) is used widely in clinical environments to assess severity of autism based on observation of children . 516 | A pediatrician commonly performs a preliminary investigation by taking developmental history and physically examining the child . 517 | If warranted , diagnosis and evaluations are conducted with help from ASD specialists , observing and assessing cognitive , communication , family , and other factors using standardized tools , and taking into account any associated medical conditions . 518 | A pediatric neuropsychologist is often asked to assess behavior and cognitive skills , both to aid diagnosis and to help recommend educational interventions . 519 | A differential diagnosis for ASD at this stage might also consider intellectual disability , hearing impairment , and a specific language impairment such as Landau-Kleffner syndrome . 520 | The presence of autism can make it harder to diagnose coexisting psychiatric disorders such as depression . 521 | Clinical genetics evaluations are often done once ASD is diagnosed , particularly when other symptoms already suggest a genetic cause . 522 | Although genetic technology allows clinical geneticists to link an estimated 40 % of cases to genetic causes , consensus guidelines in the US and UK are limited to high-resolution chromosome and fragile X testing . 523 | A genotype-first model of diagnosis has been proposed , which would routinely assess the genome 's copy number variations . 524 | As new genetic tests are developed several ethical , legal , and social issues will emerge . 525 | Commercial availability of tests may precede adequate understanding of how to use test results , given the complexity of autism 's genetics . 526 | Metabolic and neuroimaging tests are sometimes helpful , but are not routine . 527 | ASD can sometimes be diagnosed by age 14 months , although diagnosis becomes increasingly stable over the first three years of life : for example , a one-year-old who meets diagnostic criteria for ASD is less likely than a three-year-old to continue to do so a few years later . 528 | In the UK the National Autism Plan for Children recommends at most 30 weeks from first concern to completed diagnosis and assessment , though few cases are handled that quickly in practice . 529 | A 2009 US study found the average age of formal ASD diagnosis was 5.7 years , far above recommendations , and that 27 % of children remained undiagnosed at age 8 years . 530 | Although the symptoms of autism and ASD begin early in childhood , they are sometimes missed ; years later , adults may seek diagnoses to help them or their friends and family understand themselves , to help their employers make adjustments , or in some locations to claim disability living allowances or other benefits . 531 | Underdiagnosis and overdiagnosis are problems in marginal cases , and much of the recent increase in the number of reported ASD cases is likely due to changes in diagnostic practices . 532 | The increasing popularity of drug treatment options and the expansion of benefits has given providers incentives to diagnose ASD , resulting in some overdiagnosis of children with uncertain symptoms . 533 | Conversely , the cost of screening and diagnosis and the challenge of obtaining payment can inhibit or delay diagnosis . 534 | It is particularly hard to diagnose autism among the visually impaired , partly because some of its diagnostic criteria depend on vision , and partly because autistic symptoms overlap with those of common blindness syndromes or blindisms . 535 | Classification . 536 | Autism is one of the five pervasive developmental disorders ( PDD ) , which are characterized by widespread abnormalities of social interactions and communication , and severely restricted interests and highly repetitive behavior . 537 | These symptoms do not imply sickness , fragility , or emotional disturbance . 538 | Of the five PDD forms , Asperger syndrome is closest to autism in signs and likely causes ; Rett syndrome and childhood disintegrative disorder share several signs with autism , but may have unrelated causes ; PDD not otherwise specified ( PDD-NOS ; also called " atypical autism " ) is diagnosed when the criteria are not met for a more specific disorder . 539 | Unlike with autism , people with Asperger syndrome have no substantial delay in language development . 540 | The terminology of autism can be bewildering , with autism , Asperger syndrome and PDD-NOS often called the " autism spectrum disorders " ( ASD ) or sometimes the " autistic disorders " , whereas autism itself is often called " autistic disorder " , " childhood autism " , or " infantile autism " . 541 | In this article , " autism " refers to the classic autistic disorder ; in clinical practice , though , " autism " , " ASD " , and " PDD " are often used interchangeably . 542 | ASD , in turn , is a subset of the broader autism phenotype , which describes individuals who may not have ASD but do have autistic-like traits , such as avoiding eye contact . 543 | The manifestations of autism cover a wide spectrum , ranging from individuals with severe impairments -- who may be silent , mentally disabled , and locked into hand flapping and rocking -- to high functioning individuals who may have active but distinctly odd social approaches , narrowly focused interests , and verbose , pedantic communication . 544 | Because the behavior spectrum is continuous , boundaries between diagnostic categories are necessarily somewhat arbitrary . 545 | Sometimes the syndrome is divided into low- , medium- or high-functioning autism ( LFA , MFA , and HFA ) , based on IQ thresholds , or on how much support the individual requires in daily life ; these subdivisions are not standardized and are controversial . 546 | Autism can also be divided into syndromal and non-syndromal autism ; the syndromal autism is associated with severe or profound intellectual disability or a congenital syndrome with physical symptoms , such as tuberous sclerosis . 547 | Although individuals with Asperger syndrome tend to perform better cognitively than those with autism , the extent of the overlap between Asperger syndrome , HFA , and non-syndromal autism is unclear . 548 | Some studies have reported diagnoses of autism in children due to a loss of language or social skills , as opposed to a failure to make progress , typically from 15 to 30 months of age . 549 | The validity of this distinction remains controversial ; it is possible that regressive autism is a specific subtype , or that there is a continuum of behaviors between autism with and without regression . 550 | Research into causes has been hampered by the inability to identify biologically meaningful subgroups within the autistic population and by the traditional boundaries between the disciplines of psychiatry , psychology , neurology and pediatrics . 551 | Newer technologies such as fMRI and diffusion tensor imaging can help identify biologically relevant phenotypes ( observable traits ) that can be viewed on brain scans , to help further neurogenetic studies of autism ; one example is lowered activity in the fusiform face area of the brain , which is associated with impaired perception of people versus objects . 552 | It has been proposed to classify autism using genetics as well as behavior . 553 | Screening . 554 | About half of parents of children with ASD notice their child 's unusual behaviors by age 18 months , and about four-fifths notice by age 24 months . 555 | According to an article in the " Journal of Autism and Developmental Disorders " , failure to meet any of the following milestones " is an absolute indication to proceed with further evaluations . 556 | Delay in referral for such testing may delay early diagnosis and treatment and affect the long-term outcome " . 557 | US and Japanese practice is to screen all children for ASD at 18 and 24 months , using autism-specific formal screening tests . 558 | In contrast , in the UK , children whose families or doctors recognize possible signs of autism are screened . 559 | It is not known which approach is more effective . 560 | Screening tools include the Modified Checklist for Autism in Toddlers ( M-CHAT ) , the Early Screening of Autistic Traits Questionnaire , and the First Year Inventory ; initial data on M-CHAT and its predecessor CHAT on children aged 18-30 months suggests that it is best used in a clinical setting and that it has low sensitivity ( many false-negatives ) but good specificity ( few false-positives ) . 561 | It may be more accurate to precede these tests with a broadband screener that does not distinguish ASD from other developmental disorders . 562 | Screening tools designed for one culture 's norms for behaviors like eye contact may be inappropriate for a different culture . 563 | Although genetic screening for autism is generally still impractical , it can be considered in some cases , such as children with neurological symptoms and dysmorphic features . 564 | Management . 565 | The main goals when treating children with autism are to lessen associated deficits and family distress , and to increase quality of life and functional independence . 566 | No single treatment is best and treatment is typically tailored to the child 's needs . 567 | Families and the educational system are the main resources for treatment . 568 | Studies of interventions have methodological problems that prevent definitive conclusions about efficacy . 569 | Although many psychosocial interventions have some positive evidence , suggesting that some form of treatment is preferable to no treatment , the methodological quality of systematic reviews of these studies has generally been poor , their clinical results are mostly tentative , and there is little evidence for the relative effectiveness of treatment options . 570 | Intensive , sustained special education programs and behavior therapy early in life can help children acquire self-care , social , and job skills , and often improve functioning and decrease symptom severity and maladaptive behaviors ; claims that intervention by around age three years is crucial are not substantiated . 571 | Available approaches include applied behavior analysis ( ABA ) , developmental models , structured teaching , speech and language therapy , social skills therapy , and occupational therapy . 572 | There is some evidence that early intensive behavioral intervention , an early intervention model for 20 to 40 hours a week for multiple years , is an effective behavioral treatment for some children with ASD . 573 | 574 | Educational interventions can be effective to varying degrees in most children : intensive ABA treatment has demonstrated effectiveness in enhancing global functioning in preschool children and is well-established for improving intellectual performance of young children . 575 | Neuropsychological reports are often poorly communicated to educators , resulting in a gap between what a report recommends and what education is provided . 576 | It is not known whether treatment programs for children lead to significant improvements after the children grow up , and the limited research on the effectiveness of adult residential programs shows mixed results . 577 | The appropriateness of including children with varying severity of autism spectrum disorders in the general education population is a subject of current debate among educators and researchers . 578 | Many medications are used to treat ASD symptoms that interfere with integrating a child into home or school when behavioral treatment fails . 579 | More than half of US children diagnosed with ASD are prescribed psychoactive drugs or anticonvulsants , with the most common drug classes being antidepressants , stimulants , and antipsychotics . 580 | Aside from antipsychotics , there is scant reliable research about the effectiveness or safety of drug treatments for adolescents and adults with ASD . 581 | A person with ASD may respond atypically to medications , the medications can have adverse effects , and no known medication relieves autism 's core symptoms of social and communication impairments . 582 | Experiments in mice have reversed or reduced some symptoms related to autism by replacing or modulating gene function , suggesting the possibility of targeting therapies to specific rare mutations known to cause autism . 583 | Although many alternative therapies and interventions are available , few are supported by scientific studies . 584 | Treatment approaches have little empirical support in quality-of-life contexts , and many programs focus on success measures that lack predictive validity and real-world relevance . 585 | Scientific evidence appears to matter less to service providers than program marketing , training availability , and parent requests . 586 | Some alternative treatments may place the child at risk . 587 | A 2008 study found that compared to their peers , autistic boys have significantly thinner bones if on casein-free diets ; in 2005 , botched chelation therapy killed a five-year-old child with autism . 588 | Treatment is expensive ; indirect costs are more so . 589 | For someone born in 2000 , a US study estimated an average lifetime cost of $ ( net present value in dollars , inflation-adjusted from 2003 estimate ) , with about 10 % medical care , 30 % extra education and other care , and 60 % lost economic productivity . 590 | Publicly supported programs are often inadequate or inappropriate for a given child , and unreimbursed out-of-pocket medical or therapy expenses are associated with likelihood of family financial problems ; one 2008 US study found a 14 % average loss of annual income in families of children with ASD , and a related study found that ASD is associated with higher probability that child care problems will greatly affect parental employment . 591 | US states increasingly require private health insurance to cover autism services , shifting costs from publicly funded education programs to privately funded health insurance . 592 | After childhood , key treatment issues include residential care , job training and placement , sexuality , social skills , and estate planning . 593 | Prognosis . 594 | There is no known cure . 595 | Children recover occasionally , so that they lose their diagnosis of ASD ; this occurs sometimes after intensive treatment and sometimes not . 596 | It is not known how often recovery happens ; reported rates in unselected samples of children with ASD have ranged from 3 % to 25 % . 597 | Most autistic children can acquire language by age 5 or younger , though a few have developed communication skills in later years . 598 | Most children with autism lack social support , meaningful relationships , future employment opportunities or self-determination . 599 | Although core difficulties tend to persist , symptoms often become less severe with age . 600 | Few high-quality studies address long-term prognosis . 601 | Some adults show modest improvement in communication skills , but a few decline ; no study has focused on autism after midlife . 602 | Acquiring language before age six , having an IQ above 50 , and having a marketable skill all predict better outcomes ; independent living is unlikely with severe autism . 603 | A 2004 British study of 68 adults who were diagnosed before 1980 as autistic children with IQ above 50 found that 12 % achieved a high level of independence as adults , 10 % had some friends and were generally in work but required some support , 19 % had some independence but were generally living at home and needed considerable support and supervision in daily living , 46 % needed specialist residential provision from facilities specializing in ASD with a high level of support and very limited autonomy , and 12 % needed high-level hospital care . 604 | A 2005 Swedish study of 78 adults that did not exclude low IQ found worse prognosis ; for example , only 4 % achieved independence . 605 | A 2008 Canadian study of 48 young adults diagnosed with ASD as preschoolers found outcomes ranging through poor ( 46 % ) , fair ( 32 % ) , good ( 17 % ) , and very good ( 4 % ) ; 56 % of these young adults had been employed at some point during their lives , mostly in volunteer , sheltered or part-time work . 606 | Changes in diagnostic practice and increased availability of effective early intervention make it unclear whether these findings can be generalized to recently diagnosed children . 607 | Epidemiology . 608 | Most recent reviews tend to estimate a prevalence of 1-2 per 1,000 for autism and close to 6 per 1,000 for ASD , and 11 per 1,000 children in the United States for ASD as of 2008 ; because of inadequate data , these numbers may underestimate ASD 's true prevalence . 609 | PDD-NOS 's prevalence has been estimated at 3.7 per 1,000 , Asperger syndrome at roughly 0.6 per 1,000 , and childhood disintegrative disorder at 0.02 per 1,000 . 610 | The number of reported cases of autism increased dramatically in the 1990s and early 2000s . 611 | This increase is largely attributable to changes in diagnostic practices , referral patterns , availability of services , age at diagnosis , and public awareness , though unidentified environmental risk factors can not be ruled out . 612 | The available evidence does not rule out the possibility that autism 's true prevalence has increased ; a real increase would suggest directing more attention and funding toward changing environmental factors instead of continuing to focus on genetics . 613 | Boys are at higher risk for ASD than girls . 614 | The sex ratio averages 4.3:1 and is greatly modified by cognitive impairment : it may be close to 2:1 with intellectual disability and more than 5.5:1 without . 615 | Several theories about the higher prevalence in males have been investigated , but the cause of the difference is unconfirmed . 616 | Although the evidence does not implicate any single pregnancy-related risk factor as a cause of autism , the risk of autism is associated with advanced age in either parent , and with diabetes , bleeding , and use of psychiatric drugs in the mother during pregnancy . 617 | The risk is greater with older fathers than with older mothers ; two potential explanations are the known increase in mutation burden in older sperm , and the hypothesis that men marry later if they carry genetic liability and show some signs of autism . 618 | Most professionals believe that race , ethnicity , and socioeconomic background do not affect the occurrence of autism . 619 | Several other conditions are common in children with autism . 620 | They include : 621 | History . 622 | A few examples of autistic symptoms and treatments were described long before autism was named . 623 | The " Table Talk " of Martin Luther , compiled by his notetaker , Mathesius , contains the story of a 12-year-old boy who may have been severely autistic . 624 | Luther reportedly thought the boy was a soulless mass of flesh possessed by the devil , and suggested that he be suffocated , although a later critic has cast doubt on the veracity of this report . 625 | The earliest well-documented case of autism is that of Hugh Blair of Borgue , as detailed in a 1747 court case in which his brother successfully petitioned to annul Blair 's marriage to gain Blair 's inheritance . 626 | The Wild Boy of Aveyron , a feral child caught in 1798 , showed several signs of autism ; the medical student Jean Itard treated him with a behavioral program designed to help him form social attachments and to induce speech via imitation . 627 | The New Latin word " autismus " ( English translation " autism " ) was coined by the Swiss psychiatrist Eugen Bleuler in 1910 as he was defining symptoms of schizophrenia . 628 | He derived it from the Greek word " autos " ( alpha <1F50> tauomicronsigma , meaning " self " ) , and used it to mean morbid self-admiration , referring to " autistic withdrawal of the patient to his fantasies , against which any influence from outside becomes an intolerable disturbance " . 629 | The word " autism " first took its modern sense in 1938 when Hans Asperger of the Vienna University Hospital adopted Bleuler 's terminology " autistic psychopaths " in a lecture in German about child psychology . 630 | Asperger was investigating an ASD now known as Asperger syndrome , though for various reasons it was not widely recognized as a separate diagnosis until 1981 . 631 | Leo Kanner of the Johns Hopkins Hospital first used " autism " in its modern sense in English when he introduced the label " early infantile autism " in a 1943 report of 11 children with striking behavioral similarities . 632 | Almost all the characteristics described in Kanner 's first paper on the subject , notably " autistic aloneness " and " insistence on sameness " , are still regarded as typical of the autistic spectrum of disorders . 633 | It is not known whether Kanner derived the term independently of Asperger . 634 | Kanner 's reuse of " autism " led to decades of confused terminology like " infantile schizophrenia " , and child psychiatry 's focus on maternal deprivation led to misconceptions of autism as an infant 's response to " refrigerator mothers " . 635 | Starting in the late 1960s autism was established as a separate syndrome by demonstrating that it is lifelong , distinguishing it from intellectual disability and schizophrenia and from other developmental disorders , and demonstrating the benefits of involving parents in active programs of therapy . 636 | As late as the mid-1970s there was little evidence of a genetic role in autism ; now it is thought to be one of the most heritable of all psychiatric conditions . 637 | Although the rise of parent organizations and the destigmatization of childhood ASD have deeply affected how we view ASD , parents continue to feel social stigma in situations where their autistic children 's behaviors are perceived negatively by others , and many primary care physicians and medical specialists still express some beliefs consistent with outdated autism research . 638 | The Internet has helped autistic individuals bypass nonverbal cues and emotional sharing that they find so hard to deal with , and has given them a way to form online communities and work remotely . 639 | Sociological and cultural aspects of autism have developed : some in the community seek a cure , while others believe that autism is simply another way of being . 640 | Albedo 641 | Albedo ( ) , or " reflection coefficient " , derived from Latin " albedo " " whiteness " ( or reflected sunlight ) in turn from " albus " " white , " is the diffuse reflectivity or reflecting power of a surface . 642 | It is the ratio of reflected radiation from the surface to incident radiation upon it . 643 | Its dimensionless nature lets it be expressed as a percentage and is measured on a scale from zero for no reflection of a perfectly black surface to 1 for perfect reflection of a white surface . 644 | Albedo depends on the frequency of the radiation . 645 | When quoted unqualified , it usually refers to some appropriate average across the spectrum of visible light . 646 | In general , the albedo depends on the directional distribution of incident radiation , except for Lambertian surfaces , which scatter radiation in all directions according to a cosine function and therefore have an albedo that is independent of the incident distribution . 647 | In practice , a bidirectional reflectance distribution function ( BRDF ) may be required to accurately characterize the scattering properties of a surface , but albedo is very useful as a first approximation . 648 | The albedo is an important concept in climatology , astronomy , and calculating reflectivity of surfaces in LEED sustainable-rating systems for buildings . 649 | The average overall albedo of Earth , its " planetary albedo " , is 30 to 35 % because of cloud cover , but widely varies locally across the surface because of different geological and environmental features . 650 | The term was introduced into optics by Johann Heinrich Lambert in his 1760 work " Photometria " . 651 | Terrestrial albedo . 652 | Albedos of typical materials in visible light range from up to 0.9 for fresh snow to about 0.04 for charcoal , one of the darkest substances . 653 | Deeply shadowed cavities can achieve an effective albedo approaching the zero of a black body . 654 | When seen from a distance , the ocean surface has a low albedo , as do most forests , whereas desert areas have some of the highest albedos among landforms . 655 | Most land areas are in an albedo range of 0.1 to 0.4 . 656 | The average albedo of the Earth is about 0.3 . 657 | This is far higher than for the ocean primarily because of the contribution of clouds . 658 | The Earth 's surface albedo is regularly estimated via Earth observation satellite sensors such as NASA 's MODIS instruments on board the Terra and Aqua satellites . 659 | As the total amount of reflected radiation can not be directly measured by satellite , a mathematical model of the BRDF is used to translate a sample set of satellite reflectance measurements into estimates of directional-hemispherical reflectance and bi-hemispherical reflectance ( e.g. ) . 660 | The Earth 's average surface temperature due to its albedo and the greenhouse effect is currently about 15 degreesC . 661 | If the Earth was frozen entirely ( and hence be more reflective ) the average temperature of the planet would drop below -40 degreesC If only the continental land masses became covered by glaciers , the mean temperature of the planet would drop to about 0 degreesC . 662 | In contrast , if all the ice on Earth were to melt -- a so-called aquaplanet -- the average temperature on the planet would rise to just under 27 degreesC . 663 | White-sky and black-sky albedo . 664 | It has been shown that for many applications involving terrestrial albedo , the albedo at a particular solar zenith angle " theta " " i " can reasonably be approximated by the proportionate sum of two terms : the directional-hemispherical reflectance at that solar zenith angle , formula_1 , and the bi-hemispherical reflectance , formula_2 the proportion concerned being defined as the proportion of diffuse illumination formula_3 . 665 | Albedo formula_4 can then be given as : 666 | Directional-hemispherical reflectance is sometimes referred to as black-sky albedo and bi-hemispherical reflectance as white-sky albedo . 667 | These terms are important because they allow the albedo to be calculated for any given illumination conditions from a knowledge of the intrinsic properties of the surface . 668 | Astronomical albedo . 669 | The albedos of planets , satellites and asteroids can be used to infer much about their properties . 670 | The study of albedos , their dependence on wavelength , lighting angle ( " phase angle " ) , and variation in time comprises a major part of the astronomical field of photometry . 671 | For small and far objects that can not be resolved by telescopes , much of what we know comes from the study of their albedos . 672 | For example , the absolute albedo can indicate the surface ice content of outer solar system objects , the variation of albedo with phase angle gives information about regolith properties , while unusually high radar albedo is indicative of high metallic content in asteroids . 673 | Enceladus , a moon of Saturn , has one of the highest known albedos of any body in the Solar system , with 99 % of EM radiation reflected . 674 | Another notable high-albedo body is Eris , with an albedo of 0.96 . 675 | Many small objects in the outer solar system and asteroid belt have low albedos down to about 0.05 . 676 | A typical comet nucleus has an albedo of 0.04 . 677 | Such a dark surface is thought to be indicative of a primitive and heavily space weathered surface containing some organic compounds . 678 | The overall albedo of the Moon is around 0.12 , but it is strongly directional and non-Lambertian , displaying also a strong opposition effect . 679 | While such reflectance properties are different from those of any terrestrial terrains , they are typical of the regolith surfaces of airless solar system bodies . 680 | Two common albedos that are used in astronomy are the ( V-band ) geometric albedo ( measuring brightness when illumination comes from directly behind the observer ) and the Bond albedo ( measuring total proportion of electromagnetic energy reflected ) . 681 | Their values can differ significantly , which is a common source of confusion . 682 | In detailed studies , the directional reflectance properties of astronomical bodies are often expressed in terms of the five Hapke parameters which semi-empirically describe the variation of albedo with phase angle , including a characterization of the opposition effect of regolith surfaces . 683 | The correlation between astronomical ( geometric ) albedo , absolute magnitude and diameter is : 684 | formula_6 , 685 | where formula_7 is the astronomical albedo , formula_8 is the diameter in kilometers , and formula_9 is the absolute magnitude . 686 | Examples of terrestrial albedo effects . 687 | Illumination . 688 | Although the albedo-temperature effect is best known in colder , whiter regions on Earth , the maximum albedo is actually found in the tropics where year-round illumination is greater . 689 | The maximum is additionally in the northern hemisphere , varying between three and twelve degrees north . 690 | The minima are found in the subtropical regions of the northern and southern hemispheres , beyond which albedo increases without respect to illumination . 691 | Insolation effects . 692 | The intensity of albedo temperature effects depend on the amount of albedo and the level of local insolation ; high albedo areas in the arctic and antarctic regions are cold due to low insolation , where areas such as the Sahara Desert , which also have a relatively high albedo , will be hotter due to high insolation . 693 | Tropical and sub-tropical rain forest areas have low albedo , and are much hotter than their temperate forest counterparts , which have lower insolation . 694 | Because insolation plays such a big role in the heating and cooling effects of albedo , high insolation areas like the tropics will tend to show a more pronounced fluctuation in local temperature when local albedo changes . 695 | 696 | Climate and weather . 697 | Albedo affects climate and drives weather . 698 | All weather is a result of the uneven heating of the Earth caused by different areas of the planet having different albedos . 699 | Essentially , for the driving of weather , there are two types of albedo regions jon Earth : Land and ocean . 700 | Land and ocean regions produce the four basic different types of air masses , depending on latitude and therefore insolation : Warm and dry , which form over tropical and sub-tropical land masses ; warm and wet , which form over tropical and sub-tropical oceans ; cold and dry which form over temperate , polar and sub-polar land masses ; and cold and wet , which form over temperate , polar and sub-polar oceans . 701 | Different temperatures between the air masses result in different air pressures , and the masses develop into pressure systems . 702 | High pressure systems flow toward lower pressure , driving weather from north to south in the northern hemisphere , and south to north in the lower ; however due to the spinning of the Earth , the Coriolis effect further complicates flow and creates several weather/climate bands and the jet streams . 703 | Albedo-temperature feedback . 704 | When an area 's albedo changes due to snowfall , a snow-temperature feedback results . 705 | A layer of snowfall increases local albedo , reflecting away warming sunlight so local cooling occurs . 706 | In principle , if no outside temperature change affects this area ( e.g. a warm air mass ) , the lowered albedo and lower temperature would maintain the current snow and invite further snowfall , deepening the snow-temperature feedback . 707 | However , since local weather is dynamic due to the change of seasons , eventually warm air masses and a more direct angle of sunlight ( higher insolation ) cause melting . 708 | When the melted area reveals surfaces with lower albedo , such as grass or soil , the effect is reversed : the darkening surface lowers albedo , increasing local temperatures , which induces more melting and thus increasing albedo , resulting in still more heating . 709 | 710 | Small-scale effects . 711 | Albedo works on a smaller scale , too . 712 | In sunlight , dark clothes absorb more heat and light-coloured clothes reflect it better , thus allowing some control over body temperature by exploiting the albedo effect of the colour of external clothing . 713 | Trees . 714 | Because forests are generally attributed a low albedo , ( as the majority of the ultraviolet and visible spectrum is absorbed through photosynthesis ) , it has been erroneously assumed that removing forests would lead to cooling on the grounds of increased albedo . 715 | Through the evapotranspiration of water , trees discharge excess heat from the forest canopy . 716 | This water vapour rises resulting in cloud cover which also has a high albedo , thereby further increasing the net global cooling effect attributable to forests . 717 | In seasonally snow-covered zones , winter albedos of treeless areas are 10 % to 50 % higher than nearby forested areas because snow does not cover the trees as readily . 718 | Deciduous trees have an albedo value of about 0.15 to 0.18 whereas coniferous trees have a value of about 0.09 to 0.15 . 719 | Studies by the Hadley Centre have investigated the relative ( generally warming ) effect of albedo change and ( cooling ) effect of carbon sequestration on planting forests . 720 | They found that new forests in tropical and midlatitude areas tended to cool ; new forests in high latitudes ( e.g. Siberia ) were neutral or perhaps warming . 721 | Snow . 722 | Snow albedos can be as high as 0.9 ; this , however , is for the ideal example : fresh deep snow over a featureless landscape . 723 | Over Antarctica they average a little more than 0.8 . 724 | If a marginally snow-covered area warms , snow tends to melt , lowering the albedo , and hence leading to more snowmelt ( the ice-albedo positive feedback ) . 725 | Cryoconite , powdery windblown dust containing soot , sometimes reduces albedo on glaciers and ice sheets . 726 | Water . 727 | Water reflects light very differently from typical terrestrial materials . 728 | The reflectivity of a water surface is calculated using the Fresnel equations ( see graph ) . 729 | At the scale of the wavelength of light even wavy water is always smooth so the light is reflected in a locally specular manner ( not diffusely ) . 730 | The glint of light off water is a commonplace effect of this . 731 | At small angles of incident light , waviness results in reduced reflectivity because of the steepness of the reflectivity-vs.-incident-angle curve and a locally increased average incident angle . 732 | Although the reflectivity of water is very low at low and medium angles of incident light , it increases tremendously at high angles of incident light such as occur on the illuminated side of the Earth near the terminator ( early morning , late afternoon and near the poles ) . 733 | However , as mentioned above , waviness causes an appreciable reduction . 734 | Since the light specularly reflected from water does not usually reach the viewer , water is usually considered to have a very low albedo in spite of its high reflectivity at high angles of incident light . 735 | Note that white caps on waves look white ( and have high albedo ) because the water is foamed up , so there are many superimposed bubble surfaces which reflect , adding up their reflectivities . 736 | Fresh ' black ' ice exhibits Fresnel reflection . 737 | Clouds . 738 | Cloud albedo has substantial influence over atmospheric temperatures . 739 | Different types of clouds exhibit different reflectivity , theoretically ranging in albedo from a minimum of near 0 to a maximum approaching 0.8 . 740 | " On any given day , about half of Earth is covered by clouds , which reflect more sunlight than land and water . 741 | Clouds keep Earth cool by reflecting sunlight , but they can also serve as blankets to trap warmth . " 742 | Albedo and climate in some areas are affected by artificial clouds , such as those created by the contrails of heavy commercial airliner traffic . 743 | A study following the burning of the Kuwaiti oil fields during Iraqi occupation showed that temperatures under the burning oil fires were as much as 10 degreesC colder than temperatures several miles away under clear skies . 744 | Aerosol effects . 745 | Aerosols ( very fine particles/droplets in the atmosphere ) have both direct and indirect effects on the Earth 's radiative balance . 746 | The direct ( albedo ) effect is generally to cool the planet ; the indirect effect ( the particles act as cloud condensation nuclei and thereby change cloud properties ) is less certain . 747 | As per the effects are : 748 | Black carbon . 749 | Another albedo-related effect on the climate is from black carbon particles . 750 | The size of this effect is difficult to quantify : the Intergovernmental Panel on Climate Change estimates that the global mean radiative forcing for black carbon aerosols from fossil fuels is +0.2 W m-2 , with a range +0.1 to +0.4 W m-2 . 751 | Human Activities . 752 | Human activities ( e.g. deforestation , farming , and urbanization ) change the albedo of various areas around the globe . 753 | However , quantification of this effect on the global scale is difficult . 754 | Other types of albedo . 755 | Single-scattering albedo is used to define scattering of electromagnetic waves on small particles . 756 | It depends on properties of the material ( refractive index ) ; the size of the particle or particles ; and the wavelength of the incoming radiation . 757 | A 758 | A ( named " a " , plural " aes " ) is the first letter and vowel in the ISO basic Latin alphabet . 759 | It is similar to the Ancient Greek letter alpha , from which it derives . 760 | The upper-case version consists of two more or less vertical lines , joined at the top , and crossed in their middle by an horizontal bar . 761 | Origins . 762 | The earliest certain ancestor of " A " is aleph ( also called ' aleph ) , the first letter of the Phoenician alphabet ( which , by consisting entirely of consonants , is an abjad rather than a true alphabet ) . 763 | In turn , the origin of aleph may have been a pictogram of an ox head in proto-Sinaitic script influenced by Egyptian hieroglyphs , styled as a triangular head with two horns extended . 764 | In 1600 B.C.E. , the Phoenician alphabet 's letter had a linear form that served as the base for some later forms . 765 | Its name must have corresponded closely to the Hebrew or Arabic aleph . 766 | When the ancient Greeks adopted the alphabet , they had no use for the glottal stop -- the first phoneme of the Phoenician pronunciation of the letter , and the sound that the letter denoted in Phoenician and other Semitic languages -- so they used an adaptation of the sign to represent the vowel , and gave it the similar name of alpha . 767 | In the earliest Greek inscriptions after the Greek Dark Ages , dating to the 8th century BC , the letter rests upon its side , but in the Greek alphabet of later times it generally resembles the modern capital letter , although many local varieties can be distinguished by the shortening of one leg , or by the angle at which the cross line is set . 768 | The Etruscans brought the Greek alphabet to their civilization in the Italian Peninsula and left the letter unchanged . 769 | The Romans later adopted the Etruscan alphabet to write the Latin language , and the resulting letter was preserved in the Latin alphabet used to write many languages , including English . 770 | During Roman times , there were many variations on the letter " A " . 771 | First was the monumental or lapidary style , which was used when inscribing on stone or other " permanent " mediums . 772 | For perishable surfaces , what was used for everyday or utilitarian purposes , a cursive style was used . 773 | Due to the " perishable " nature of the surfaces , these examples are not as prevalent as the monumental . 774 | This perishable style was called cursive and numerous variations have survived , such as majuscule cursive , minuscule cursive , semicursive minuscule . 775 | There were also variants that were intermediate between the monumental and the cursive . 776 | The known variants include the early semi-uncial , the uncial , and the later semi-uncial . 777 | At the termination of the Roman Empire ( 5th century AD ) , several variants of the cursive minuscule appeared through Western Europe . 778 | Among these were the semicursive minuscule of Italy , the Merovingian script in France , the Visigothic script in Spain , and the Insular or Anglo-Irish semi-uncial or Anglo-Saxon majuscule , of Great Britain . 779 | By the 9th century , the Caroline script , which was very similar to the present-day form , was the principal form used in book-making , before the advent of the printing press . 780 | This form was derived through a combining of prior forms . 781 | 15th-century Italy saw the formation of the two variants that are known today . 782 | These variants , the " Italics " and " Roman " forms , were derived from the Caroline Script version . 783 | The Italics form used in most current handwriting consists of a circle and vertical stroke ( ) , called Latin alpha or " script a " . 784 | This slowly developed from the fifth-century form resembling the Greek letter tau in the hands of dark-age Irish and English writers . 785 | Most printed material uses the Roman form consisting of a small loop with an arc over it ( ) . 786 | Both derive from the majuscule ( capital ) form . 787 | In Greek handwriting , it was common to join the left leg and horizontal stroke into a single loop , as demonstrated by the uncial version shown . 788 | Many fonts then made the right leg vertical . 789 | In some of these , the serif that began the right leg stroke developed into an arc , resulting in the printed form , while in others it was dropped , resulting in the modern handwritten form . 790 | Use in English . 791 | In English , the letter A currently represents six different vowel sounds : A by itself frequently denotes the near-open front unrounded vowel ( ) as in " pad " ; the open back unrounded vowel ( ) as in " father " , its original , Latin and Greek , sound ; a closer , further fronted sound as in " hare " , which developed as the sound progressed from " father " to " ace " ; in concert with a later orthographic vowel , the diphthong as in " ace " and " major " , due to effects of the great vowel shift ; the more rounded form in " water " or its closely related cousin , found in " was " . 792 | A is a common symbol of school and basic phonetics in the US , along with B and C 793 | The double " a " sequence is not a native English combination ; however it is used this way in some foreign words such as " Aaron " and " aardvark " . 794 | " A " is the third-most-commonly used letter in English ( after " E " and " T " ) , and the second most common in Spanish and French . 795 | In one study , on average , about 3.68 % of letters used in English tend to be ' a ' , while the number is 6.22 % in Spanish and 3.95 % in French . 796 | " A " is often used to denote something or someone of a better or more prestigious quality or status : A- , A or A+ , the best grade that can be assigned by teachers for students ' schoolwork ; " A grade " for clean restaurants ; A-List celebrities , etc . 797 | Such associations can have a motivating effect , as exposure to the letter A has been found to improve performance , when compared with other letters . 798 | The letter " A " along with other letters at the beginning of the alphabet are used in algebra to represent known quantities . 799 | Whereas the letters at the end of the alphabet ( x,y,z ) are used to denote unknown quantities . 800 | Also , in geometry , the capital A , B , C etc. are used to denote segments , lines , rays , etc . 801 | Also , A is typically used as one of the letters to represent an angle in a triangle . 802 | In logic , A is used to signify the universal affirmative . 803 | Finally , the letter A is used to denote sized , as in a narrow size shoe , or a small cup size in a brassiere . 804 | Use in other languages . 805 | In most languages that use the Latin alphabet , A denotes an open unrounded vowel : , , or . 806 | An exception is Saanich , in which A ( and A ) stand for a close-mid front unrounded vowel . 807 | In the , variants of A denote various vowels . 808 | In X-SAMPA , capital A denotes the open back unrounded vowel and lowercase a denotes the open front unrounded vowel . 809 | Alabama 810 | Alabama ( ) is a state located in the southeastern region of the United States . 811 | It is bordered by Tennessee to the north , Georgia to the east , Florida and the Gulf of Mexico to the south , and Mississippi to the west . 812 | Alabama is the 30th-most extensive and the 23rd-most populous of the 50 United States . 813 | At , Alabama has one of the longest navigable inland waterways in the nation . 814 | From the American Civil War until World War II , Alabama , like many Southern states , suffered economic hardship , in part because of continued dependence on agriculture . 815 | Despite the growth of major industries and urban centers , White rural interests dominated the state legislature until the 1960s , while urban interests and African Americans were under-represented . 816 | Following World War II , Alabama experienced growth as the economy of the state transitioned from one primarily based on agriculture to one with diversified interests . 817 | The establishment or expansion of multiple United States Armed Forces installations added to the state economy and helped bridge the gap between an agricultural and industrial economy during the mid-20th century . 818 | The state economy in the 21st century is dependent on management , automotive , finance , manufacturing , aerospace , mineral extraction , healthcare , education , retail , and technology . 819 | Alabama is unofficially nicknamed the " Yellowhammer State " , after the state bird . 820 | Alabama is also known as the " Heart of Dixie " . 821 | The state tree is the Longleaf Pine , the state flower is the Camellia . 822 | The capital of Alabama is Montgomery . 823 | The largest city by population is Birmingham . 824 | The largest city by total land area is Huntsville . 825 | The oldest city is Mobile , founded by French colonists . 826 | Etymology . 827 | The Alabama people , a Muskogean-speaking tribe whose members lived just below the confluence of the Coosa and Tallapoosa rivers on the upper reaches of the Alabama River , were the origin of later European-American naming of the river and state . 828 | In the Alabama language , the word for an Alabama person is " Albaamo " ( or variously " Albaama " or " Albaamo " in different dialects ; the plural form is " Albaamaha " ) . 829 | The word " Alabama " is believed to have come from the related Choctaw language and was adopted by the Alabama tribe as their name . 830 | The spelling of the word varies significantly among historical sources . 831 | The first usage appears in three accounts of the Hernando de Soto expedition of 1540 with Garcilaso de la Vega using " Alibamo " , while the Knight of Elvas and Rodrigo Ranjel wrote " Alibamu " and " Limamu " , respectively , in efforts to transliterate the term . 832 | As early as 1702 , the French called the tribe the " Alibamon , " with French maps identifying the river as " Riviere des Alibamons " . 833 | Other spellings of the appellation have included " Alibamu " , " Alabamo " , " Albama " , " Alebamon " , " Alibama " , " Alibamou " , " Alabamu " , and " Allibamou " . 834 | Sources disagree on the meaning of the word . 835 | An 1842 article in the " Jacksonville Republican " proposed that it meant " Here We Rest. " This notion was popularized in the 1850s through the writings of Alexander Beaufort Meek . 836 | Experts in the Muskogean languages have been unable to find any evidence to support such a translation . 837 | Scholars believe the word comes from the Choctaw " alba " ( meaning " plants " or " weeds " ) and " amo " ( meaning " to cut " , " to trim " , or " to gather " ) . 838 | The meaning may have been " clearers of the thicket " or " herb gatherers " , referring to clearing land for cultivation or collecting medicinal plants . 839 | The state has numerous place names of Native American origin . 840 | History . 841 | Pre-European settlement . 842 | Indigenous peoples of varying cultures lived in the area for thousands of years before European colonization . 843 | Trade with the northeastern tribes via the Ohio River began during the Burial Mound Period ( 1000 BC-AD 700 ) and continued until European contact . 844 | The agrarian Mississippian culture covered most of the state from 1000 to 1600 AD , with one of its major centers built at what is now the Moundville Archaeological Site in Moundville , Alabama . 845 | Analysis of artifacts recovered from archaeological excavations at Moundville were the basis of scholars ' formulating the characteristics of the Southeastern Ceremonial Complex ( SECC ) . 846 | Contrary to popular belief , the SECC appears to have no direct links to Mesoamerican culture , but developed independently . 847 | The Ceremonial Complex represents a major component of the religion of the Mississippian peoples ; it is one of the primary means by which their religion is understood . 848 | Among the historical tribes of Native American people living in the area of present-day Alabama at the time of European contact were the Cherokee , an Iroquoian language people ; and the Muskogean-speaking Alabama ( " Alibamu " ) , Chickasaw , Choctaw , Creek , and Koasati . 849 | While part of the same large language family , the Muskogee tribes developed distinct cultures and languages . 850 | European settlement . 851 | With exploration in the 16th century , the Spanish were the first Europeans to reach Alabama . 852 | The expedition of Hernando de Soto passed through Mabila and other parts of the state in 1540 . 853 | More than 160 years later , the French founded the first European settlement in the region at Old Mobile in 1702 . 854 | The city was moved to the current site of Mobile in 1711 . 855 | This area was claimed by the French from 1702 to 1763 as part of La Louisiane . 856 | After the French lost to the British in the Seven Years War , it became part of British West Florida from 1763 to 1783 . 857 | After the United States victory in the American Revolutionary War , the territory was divided between the United States and Spain . 858 | The latter retained control of this western territory from 1783 until the surrender of the Spanish garrison at Mobile to U.S. forces on April 13 , 1813 . 859 | Thomas Bassett , a loyalist to the British monarchy during the Revolutionary era , was one of the earliest White settlers in the state outside of Mobile . 860 | He settled in the Tombigbee District during the early 1770s . 861 | The boundaries of the district were roughly limited to the area within a few miles of the Tombigbee River and included portions of what is today southern Clarke County , northernmost Mobile County , and most of Washington County . 862 | What is now the counties of Baldwin and Mobile became part of Spanish West Florida in 1783 , part of the independent Republic of West Florida in 1810 , and was finally added to the Mississippi Territory in 1812 . 863 | Most of what is now the northern two-thirds of Alabama was known as the Yazoo lands beginning during the British colonial period . 864 | It was claimed by the Province of Georgia from 1767 onwards . 865 | Following the Revolutionary War , it remained a part of Georgia , although heavily disputed . 866 | With the exception of the immediate area around Mobile and the Yazoo lands , what is now the lower one-third Alabama was made part of the Mississippi Territory when it was organized in 1798 . 867 | The Yazoo lands were added to the territory in 1804 , following the Yazoo land scandal . 868 | Spain kept a claim on its former Spanish West Florida territory in what would become the coastal counties until the Adams-Onis Treaty officially ceded it to the United States in 1819 . 869 | Nineteenth century . 870 | Prior to the admission of Mississippi as a state on December 10 , 1817 , the more sparsely settled eastern half of the territory was separated and named the Alabama Territory . 871 | The Alabama Territory was created by the United States Congress on March 3 , 1817 . 872 | St . 873 | Stephens , now abandoned , served as the territorial capital from 1817 to 1819 . 874 | The U.S . 875 | Congress selected Huntsville as the site for the first Constitutional Convention of Alabama after it was approved to become the 22nd state . 876 | From July 5 to August 2 , 1819 , delegates met to prepare the new state constitution . 877 | Huntsville served as the temporary capital of Alabama from 1819 to 1820 , when the seat of state government was moved to Cahaba in Dallas County . 878 | Cahaba , now a ghost town , was the first permanent state capital from 1820 to 1825 . 879 | Alabama Fever was already underway when the state was admitted to the Union , with settlers and land speculators pouring into the state to take advantage of fertile land suitable for cotton cultivation . 880 | Part of the frontier in the 1820s and 1830s , its constitution provided for universal suffrage for White men . 881 | Southeastern planters and traders from the Upper South brought slaves with them as the cotton plantations in Alabama expanded . 882 | The economy of the central Black Belt ( named for its dark , productive soil ) was built around large cotton plantations whose owners ' wealth grew largely from slave labor . 883 | The area also drew many poor , disfranchised people who became subsistence farmers . 884 | Alabama had a population estimated at under 10,000 people in 1810 , but it had increased to more than 300,000 people by 1830 . 885 | Most Native American tribes were completely removed from the state within a few years of the passage of the Indian Removal Act by Congress in 1830 . 886 | From 1826 to 1846 , Tuscaloosa served as the capital of Alabama . 887 | On January 30 , 1846 , the Alabama legislature announced that it had voted to remove the capital city from Tuscaloosa to Montgomery . 888 | The first legislative session in the new capital met in December 1847 . 889 | A new capitol building was erected under the direction of Stephen Decatur Button of Philadelphia . 890 | The first structure burned down in 1849 , but was rebuilt on the same site in 1851 . 891 | This second capitol building in Montgomery remains to the present day . 892 | It was designed by Barachias Holt of Exeter , Maine . 893 | By 1860 the population had increased to a total of 964,201 people , of which 435,080 were enslaved African Americans and 2,690 were free people of color . 894 | On January 11 , 1861 , Alabama declared its secession from the Union . 895 | After remaining an independent republic for a few days , it joined the Confederate States of America . 896 | The Confederacy 's capital was initially located at Montgomery . 897 | Alabama was heavily involved in the American Civil War . 898 | Although comparatively few battles were fought in the state , Alabama contributed about 120,000 soldiers to the war effort . 899 | A company of cavalry soldiers from Huntsville , Alabama joined Nathan Bedford Forrest 's battalion in Hopkinsville , Kentucky . 900 | The company wore new uniforms with yellow trim on the sleeves , collar and coat tails . 901 | This led to them being greeted with " Yellowhammer " , and the name later was applied to all Alabama troops in the Confederate Army . 902 | Alabama 's slaves were freed by the 13th Amendment in 1865 . 903 | Alabama was under military rule from the end of the war in May 1865 until its official restoration to the Union in 1868 . 904 | From 1867 to 1874 , with most White citizens barred from voting , many African Americans emerged as political leaders in the state . 905 | Alabama was represented in Congress during this period by three African American congressmen : Jeremiah Haralson , Benjamin S. Turner , and James T. Rapier . 906 | Following the war , the state remained chiefly agricultural , with an economy tied to cotton . 907 | During Reconstruction , state legislators ratified a new state constitution in 1868 that created a public school system for the first time and expanded women 's rights . 908 | Legislators funded numerous public road and railroad projects , although these were plagued with allegations of fraud and misappropriation . 909 | Organized resistance groups also tried to suppress the freedmen and Republicans . 910 | Besides the short-lived original Ku Klux Klan , these included the Pale Faces , Knights of the White Camellia , Red Shirts , and the White League . 911 | Reconstruction in Alabama ended in 1874 , when the Democrats regained control of the legislature and governor 's office . 912 | They wrote another constitution in 1875 , and the legislature passed the Blaine Amendment , prohibiting public money from being used to finance religious affiliated schools . 913 | The same year , legislation was approved that called for racially segregated schools . 914 | Railroad passenger cars were segregated in 1891 . 915 | More Jim Crow laws were passed at the beginning of the 20th century to enforce segregation in everyday life . 916 | Twentieth century . 917 | The new 1901 Constitution of Alabama included electoral laws that effectively disfranchised African Americans , Native Americans , and most poor Whites through voting restrictions , including poll taxes and literacy requirements . 918 | While the planter class had persuaded poor Whites to support these legislative efforts , the new restrictions resulted in their disfranchisement as well , due mostly to the imposition of a cumulative poll tax . 919 | In 1900 , Alabama had more than 181,000 African Americans eligible to vote . 920 | By 1903 , only 2,980 were qualified to register , although at least 74,000 African-American voters were literate . 921 | By 1941 , more White Alabamians than African-American residents had been disfranchised : a total of 600,000 Whites to 520,000 African Americans . 922 | Nearly all African Americans had lost the ability to vote , a situation that persisted until after passage of federal civil rights legislation in the 1960s to enforce their constitutional rights as citizens . 923 | The 1901 constitution reiterated that schools be racially segregated . 924 | It also restated that interracial marriage was illegal , although such marriages had been made illegal in 1867 . 925 | Further racial segregation laws were passed related to public facilities into the 1950s : jails were segregated in 1911 ; hospitals in 1915 ; toilets , hotels , and restaurants in 1928 ; and bus stop waiting rooms in 1945 . 926 | The rural-dominated Alabama legislature consistently underfunded schools and services for the disfranchised African Americans , but it did not relieve them of paying taxes . 927 | Partially as a response to chronic underfunding of education for African Americans in the South , the Rosenwald Fund began funding the construction of what came to be known as Rosenwald Schools . 928 | In Alabama these schools were designed and the construction partially financed with Rosenwald funds , which paid one-third of the construction costs . 929 | The local community and state raised matching funds to pay the rest . 930 | Black residents effectively taxed themselves twice , by raising additional monies to supply matching funds for such schools , which were built in many rural areas . 931 | Beginning in 1913 , the first 80 Rosenwald Schools were built in Alabama for African-American children . 932 | A total of 387 schools , seven teacher 's houses , and several vocational buildings had been completed in the state by 1937 . 933 | Several of the surviving school buildings in the state are now listed on the National Register of Historic Places . 934 | Continued racial discrimination , agricultural depression , and the failure of the cotton crops due to boll weevil infestation led tens of thousands of African Americans to seek opportunities in northern cities . 935 | They left Alabama in the early 20th century as part of the Great Migration to industrial jobs and better futures in northern and midwestern industrial cities . 936 | Reflecting this emigration , the population growth rate in Alabama ( see " Historical Populations " table below ) dropped by nearly half from 1910 to 1920 . 937 | At the same time , many rural people , both White and African American , moved to the city of Birmingham to work in new industrial jobs . 938 | Birmingham experienced such rapid growth that it was called " The Magic City " . 939 | By the 1920s , Birmingham was the 19th-largest city in the United States and had more than 30 % of the Alabama 's population . 940 | Heavy industry and mining were the basis of its economy . 941 | Its residents were under-represented for decades in the state legislature , which refused to redistrict to recognize demographic changes , such as urbanization . 942 | Industrial development related to the demands of World War II brought a level of prosperity to the state not seen since before the Civil War . 943 | Rural workers poured into the largest cities in the state for better jobs and a higher standard of living . 944 | One example of this massive influx of workers can be shown by what happened in Mobile . 945 | Between 1940 and 1943 , more than 89,000 people moved into the city to work for war effort industries . 946 | Cotton and other cash crops faded in importance as the state developed a manufacturing and service base . 947 | Despite massive population changes in the state from 1901 to 1961 , the rural-dominated legislature refused to reapportion House and Senate seats based on population . 948 | They held on to old representation to maintain political and economic power in agricultural areas . 949 | In addition , the state legislature gerrymandered the few Birmingham legislative seats to ensure election by persons living outside Birmingham . 950 | One result was that Jefferson County , containing Birmingham 's industrial and economic powerhouse , contributed more than one-third of all tax revenue to the state , but did not receive a proportional amount in services . 951 | Urban interests were consistently underrepresented in the legislature . 952 | A 1960 study noted that because of rural domination , " A minority of about 25 per cent of the total state population is in majority control of the Alabama legislature . " 953 | African Americans were presumed partial to Republicans for historical reasons , but they were disfranchised . 954 | White Alabamans felt bitter towards the Republican Party in the aftermath of the Civil War and Reconstruction . 955 | These factors created a longstanding tradition that any candidate who wanted to be viable with White voters had to run as a Democrat regardless of political beliefs . 956 | Although efforts had already started decades earlier , African Americans began to press to end disfranchisement and segregation in the state during the 1950s and 1960s with the Civil Rights Movement . 957 | In 1954 the US Supreme Court ruled in " Brown v . 958 | Board of Education " that public schools had to be desegated , but Alabama was slow to comply . 959 | The civil rights movement raised national awareness of the issues , leading to the enactment of the Civil Rights Act of 1964 and Voting Rights Act of 1965 by the U.S . 960 | Congress . 961 | During the 1960s , under Governor George Wallace , failed attempts were made at the state level to resist federally sanctioned desegregation efforts . 962 | During the Civil Rights Movement , African Americans achieved enforcement of voting and other civil constitutional rights through the passage of the national Civil Rights Act of 1964 , and the Voting Rights Act of 1965 . 963 | Legal segregation ended in the states as Jim Crow laws were invalidated or repealed . 964 | Under the Voting Rights Act of 1965 , cases were filed in Federal courts to force Alabama to redistrict by population both the House and Senate of the state legislature . 965 | In 1972 , for the first time since 1901 , the legislature implemented the Alabama constitution 's provision for periodic redistricting based on population . 966 | This benefited the urban areas that had developed , as well as all in the population who had been underrepresented for more than 60 years . 967 | Geography . 968 | Alabama is the thirtieth-largest state in the United States with of total area : 3.2 % of the area is water , making Alabama 23rd in the amount of surface water , also giving it the second-largest inland waterway system in the U.S . 969 | About three-fifths of the land area is a gentle plain with a general descent towards the Mississippi River and the Gulf of Mexico . 970 | The North Alabama region is mostly mountainous , with the Tennessee River cutting a large valley creating numerous creeks , streams , rivers , mountains , and lakes . 971 | The states bordering Alabama are Tennessee to the north ; Georgia to the east ; Florida to the south ; and Mississippi to the west . 972 | Alabama has coastline at the Gulf of Mexico , in the extreme southern edge of the state . 973 | Alabama ranges in elevation from sea level at Mobile Bay to over 1,800 feet ( 550 m ) in the Appalachian Mountains in the northeast . 974 | The highest point is Mount Cheaha , at a height of . 975 | Alabama 's land consists of of forest or 67 % of total land area . 976 | Suburban Baldwin County , along the Gulf Coast , is the largest county in the state in both land area and water area . 977 | Areas in Alabama administered by the National Park Service include Horseshoe Bend National Military Park near Alexander City ; Little River Canyon National Preserve near Fort Payne ; Russell Cave National Monument in Bridgeport ; Tuskegee Airmen National Historic Site in Tuskegee ; and Tuskegee Institute National Historic Site near Tuskegee . 978 | Additionally , Alabama has four National Forests : Conecuh , Talladega , Tuskegee , and William B. Bankhead . 979 | Alabama also contains the Natchez Trace Parkway , the Selma To Montgomery National Historic Trail , and the Trail Of Tears National Historic Trail . 980 | A notable natural wonder in Alabama is " Natural Bridge " rock , the longest natural bridge east of the Rockies , located just south of Haleyville . 981 | A -wide meteorite impact crater is located in Elmore County , just north of Montgomery . 982 | This is the Wetumpka crater , the site of " Alabama 's greatest natural disaster. " A -wide meteorite hit the area about 80 million years ago . 983 | The hills just east of downtown Wetumpka showcase the eroded remains of the impact crater that was blasted into the bedrock , with the area labeled the Wetumpka crater or astrobleme ( " star-wound " ) because of the concentric rings of fractures and zones of shattered rock that can be found beneath the surface . 984 | In 2002 , Christian Koeberl with the Institute of Geochemistry University of Vienna published evidence and established the site as 157th recognized impact crater on Earth . 985 | Climate . 986 | The state is classified as humid subtropical ( " Cfa " ) under the Koppen Climate Classification . 987 | The average annual temperature is 64 degreesF ( 18 degreesC ) . 988 | Temperatures tend to be warmer in the southern part of the state with its proximity to the Gulf of Mexico , while the northern parts of the state , especially in the Appalachian Mountains in the northeast , tend to be slightly cooler . 989 | Generally , Alabama has very hot summers and mild winters with copious precipitation throughout the year . 990 | Alabama receives an average of of rainfall annually and enjoys a lengthy growing season of up to 300 days in the southern part of the state . 991 | Summers in Alabama are among the hottest in the U.S. , with high temperatures averaging over throughout the summer in some parts of the state . 992 | Alabama is also prone to tropical storms and even hurricanes . 993 | Areas of the state far away from the Gulf are not immune to the effects of the storms , which often dump tremendous amounts of rain as they move inland and weaken . 994 | South Alabama reports many thunderstorms . 995 | The Gulf Coast , around Mobile Bay , averages between 70 and 80 days per year with thunder reported . 996 | This activity decreases somewhat further north in the state , but even the far north of the state reports thunder on about 60 days per year . 997 | Occasionally , thunderstorms are severe with frequent lightning and large hail ; the central and northern parts of the state are most vulnerable to this type of storm . 998 | Alabama ranks seventh in the number of deaths from lightning and ninth in the number of deaths from lightning strikes per capita . 999 | Alabama , along with Kansas , has the most reported EF5 tornadoes of any state , according to statistics from the National Climatic Data Center for the period January 1 , 1950 , to October 31 , 2006 . 1000 | Several long-tracked F5 tornadoes have contributed to Alabama reporting more tornado fatalities than any other state , even surpassing Texas which has a much larger area within Tornado Alley . 1001 | --------------------------------------------------------------------------------