├── conanfile.txt
├── tests
    ├── main.cpp
    └── CMakeLists.txt
├── src
    ├── main.cpp
    ├── Markov.hpp
    └── Markov.cpp
├── CMakeLists.txt
├── examples
    └── exampleOne.cpp
├── .gitignore
├── README.md
├── LICENSE
└── hnnews.txt


/conanfile.txt:
--------------------------------------------------------------------------------
1 | [requires]
2 | Catch2/2.5.0@catchorg/stable
3 | 
4 | [generators]
5 | cmake


--------------------------------------------------------------------------------
/tests/main.cpp:
--------------------------------------------------------------------------------
1 | #include <iostream>
2 | 
3 | 
4 | auto main() -> int {
5 |     
6 |     return 1;
7 | }


--------------------------------------------------------------------------------
/src/main.cpp:
--------------------------------------------------------------------------------
1 | #include <iostream>
2 | 
3 | auto main() -> int {
4 | 
5 |     std::cout << "Markov Chains are great " << "\n";
6 |     return 1;
7 | }


--------------------------------------------------------------------------------
/tests/CMakeLists.txt:
--------------------------------------------------------------------------------
 1 | cmake_minimum_required(VERSION 3.10)
 2 | 
 3 | project(tests)
 4 | 
 5 | 
 6 | set(FILES main.cpp)
 7 | 
 8 | add_executable(tests ${FILES})
 9 | 
10 | 


--------------------------------------------------------------------------------
/CMakeLists.txt:
--------------------------------------------------------------------------------
 1 | cmake_minimum_required(VERSION 3.10)
 2 | 
 3 | project(cppmarkov)
 4 | 
 5 | set(FILES src/main.cpp src/Markov.cpp src/Markov.hpp)
 6 | 
 7 | set(CMAKE_CXX_STANDARD 17)
 8 | 
 9 | set(CMAKE_BINARY_DIR bin)
10 | 
11 | set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
12 | 
13 | #add_subdirectory(tests)
14 | 
15 | add_executable(cppmarkov ${FILES})
16 | 
17 | 


--------------------------------------------------------------------------------
/examples/exampleOne.cpp:
--------------------------------------------------------------------------------
 1 | #include <iostream>
 2 | #include "Markov.hpp"
 3 | 
 4 | auto main() -> int {
 5 | 
 6 |     Markov::Chain chain(1);
 7 |     
 8 |     chain.add("I am sam");
 9 |     chain.add("I am an Engineer");
10 |     chain.add("I like coding");
11 | 
12 |     Markov::Ngram currentState = {"Engineer"};
13 |     Markov::NextState ns("$"); 
14 | 
15 |     std::cout << chain.transitionProbability(ns,currentState) << "\n"; // Printing 1
16 |     
17 |     return 1;
18 | }


--------------------------------------------------------------------------------
/.gitignore:
--------------------------------------------------------------------------------
 1 | # Prerequisites
 2 | *.d
 3 | 
 4 | # Compiled Object files
 5 | *.slo
 6 | *.lo
 7 | *.o
 8 | *.obj
 9 | 
10 | # Precompiled Headers
11 | *.gch
12 | *.pch
13 | 
14 | # Compiled Dynamic libraries
15 | *.so
16 | *.dylib
17 | *.dll
18 | 
19 | # Fortran module files
20 | *.mod
21 | *.smod
22 | 
23 | # Compiled Static libraries
24 | *.lai
25 | *.la
26 | *.a
27 | *.lib
28 | 
29 | # Executables
30 | *.exe
31 | *.out
32 | *.app
33 | 
34 | .idea/
35 | .vscode/
36 | cmake-build-debug/
37 | CMakeCache.txt
38 | build/
39 | bin/
40 | *.cbp
41 | cmake_install.cmake 
42 | CMakeFiles/
43 | graph_info.json


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
 1 | # cppmarkov
 2 | 
 3 | > A Markov chain is a mathematical system which keeps track of transitions between different states and tells you the probability of a transition occurring between two states.
 4 | 
 5 | This repository is an implementation in C++17 of that stochastic process. 
 6 | 
 7 | # Compiling and running the example 
 8 | 
 9 | ## Requirements 
10 | 
11 | - CMake 3.10.2 or greater
12 | - A C++ compiler (GCC or Clang etc. ) that supports C++17
13 | 
14 | ## Compiling 
15 | 
16 | In order to compile just run 
17 | 
18 | ```cmake
19 | 
20 | ~ $ cmake --build . 
21 | 
22 | ```
23 | 
24 | And the resulting binary will be in the `bin` folder.
25 | 
26 | ## Code example 
27 | 
28 | ```cpp
29 | 
30 | #include <iostream>
31 | #include "Markov.hpp"
32 | 
33 | auto main() -> int {
34 | 
35 | Markov::Chain chain(1);
36 | 
37 | chain.add("I am sam");
38 | chain.add("I am an Engineer");
39 | chain.add("I like coding");
40 | 
41 | Markov::Ngram currentState = {"Engineer"};
42 | Markov::NextState ns("$"); 
43 | 
44 | std::cout << chain.transitionProbability(ns,currentState) << "\n"; // Printing 1
45 | 
46 | return 1;
47 | }
48 | 
49 | ```
50 | 
51 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
 1 | MIT License
 2 | 
 3 | Copyright (c) 2018 Sonkeng Maldini 
 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 | 


--------------------------------------------------------------------------------
/src/Markov.hpp:
--------------------------------------------------------------------------------
  1 | #ifndef H_MARKOV_INCLUDED
  2 | #define H_MARKOV_ICLUDED
  3 | #pragma once 
  4 | 
  5 | #include <string>
  6 | #include <map>
  7 | #include <vector>
  8 | #include <sstream>
  9 | #include <iostream>
 10 | #include <random>
 11 | #include <algorithm>
 12 | 
 13 | #define START_TOKEN "^"
 14 | #define END_TOKEN "$"
 15 | 
 16 | namespace Markov {
 17 | 
 18 | //using SparseArray = std::map<std::string,int>;  // The int here is the probability from State i to State j 
 19 | using Ngram = std::vector<std::string>;
 20 | using NextState = std::string;
 21 | using Pair = std::pair<Ngram,NextState>;
 22 | 
 23 | 
 24 |     struct Occurence{
 25 |         int occurence;
 26 | 
 27 |         Occurence(){
 28 |             occurence = 1;
 29 |         }
 30 | 
 31 |         void operator++(){
 32 |             ++occurence;
 33 |         }
 34 | 
 35 |         void operator=(int i){
 36 |             occurence = i;
 37 |         }
 38 | 
 39 |          operator int (){
 40 |             return occurence;
 41 |         }
 42 |     };
 43 | 
 44 |     struct Chain {
 45 | 
 46 |         std::map<Pair,int> transitionMatrix; //
 47 |         std::map<int,Pair> ipMap_; // index pair Map
 48 |         bool computed_;
 49 |         int m_order; // The Order of the Markov Chain. 1-order , 2-order etc.
 50 |         std::vector<double> probabilities_;
 51 | 
 52 |         static int incr_;
 53 | 
 54 |         explicit Chain(int order) ;
 55 | 
 56 |         /**
 57 |          * @brief Returns the transition probability between two states
 58 |          */
 59 | 
 60 |         auto transitionProbability(const NextState& ns, const Ngram& ngram) -> double;
 61 |         
 62 |         /**
 63 |          * @brief add a new String to the chain
 64 |          */
 65 | 
 66 |         auto add(std::string&& s) -> void;
 67 | 
 68 |         /**
 69 |          * @brief Create a new pair according to the order
 70 |          */
 71 | 
 72 |         auto makePairs(std::vector<std::string>&& v,int order) -> std::vector<Pair>;
 73 |          
 74 |          /**
 75 |          * @brief Generates new text based on an initial seed
 76 |          */
 77 | 
 78 |         auto generateWord(int length) -> std::string;
 79 | 
 80 |         auto storeProbabilities() -> void ;
 81 |     };
 82 | 
 83 |     
 84 | 
 85 |     auto operator<(const Pair& lhs, const Pair& rhs) -> bool;
 86 | 
 87 |     /**
 88 |      * Helper to split string into vector
 89 |      */
 90 |     auto split(std::string str,char delimiter) -> std::vector<std::string>;
 91 | 
 92 |     /**
 93 |      * @brief take two Ngram and tell whether they're equal or not
 94 |      * @return bool
 95 |      */
 96 | 
 97 |     auto compare(const Ngram& lhs, const Ngram& rhs) -> bool;
 98 | 
 99 |     /**
100 |      * @brief Join the Ngram vector into string
101 |      */
102 |     auto join(Ngram& n) -> std::string; 
103 | }; // end namespace Markov
104 | 
105 | 
106 | #endif 


--------------------------------------------------------------------------------
/src/Markov.cpp:
--------------------------------------------------------------------------------
  1 | #include "Markov.hpp"
  2 | 
  3 | 
  4 | Markov::Chain::Chain(int order): m_order(order){}
  5 | 
  6 | auto Markov::Chain::add(std::string&& str) -> void {
  7 |     // I am sam. I am an Engineer. I like Coding.
  8 |     
  9 |     auto startTokens = std::string(START_TOKEN, m_order);
 10 |     auto endTokens   = std::string(END_TOKEN,m_order);
 11 |     str = startTokens +" " +str +" " +endTokens;
 12 | 
 13 |     //Extract N-gram from the given string 
 14 |     auto strVec = Markov::split(str,' ');
 15 | 
 16 |     std::vector<Pair> pairs = makePairs( std::move(strVec), m_order ); 
 17 | 
 18 |     for(const auto& aPair : pairs ){
 19 | 
 20 |         if( transitionMatrix.count( aPair ) ) {
 21 |             transitionMatrix[aPair]++; 
 22 |         }else{
 23 |             transitionMatrix.insert( { aPair, 1 } ); 
 24 |             ipMap_.insert( {incr_++, aPair} ); 
 25 |         }
 26 |     }
 27 | }
 28 | 
 29 | auto Markov::Chain::makePairs(std::vector<std::string>&& strVec,int order) -> std::vector<Pair>{
 30 | 
 31 |     std::vector<Pair> pairList; 
 32 | 
 33 |     for(int i(1); i < strVec.size()-order;++i){
 34 |         
 35 |         Ngram currState; 
 36 |         NextState ns; 
 37 | 
 38 |         ns = strVec.at( i+order );
 39 |         for( int j(i); j< i+order; ++j){
 40 |             currState.push_back(strVec.at(j)); 
 41 |         }
 42 | 
 43 |         pairList.push_back( { currState,ns } );
 44 |     }
 45 | 
 46 |     return pairList;
 47 | }
 48 | 
 49 | auto Markov::Chain::transitionProbability(const Markov::NextState& ns, const Markov::Ngram& currentState) -> double {
 50 |     
 51 |     if( currentState.size() != m_order){
 52 |         throw 1;
 53 |     }
 54 |     
 55 |     int frequenceOfng{0}, sumOther{0};
 56 | 
 57 |     Pair pairToLookFor{ currentState,ns };
 58 | 
 59 |     if( transitionMatrix.count( pairToLookFor ) ){
 60 | 
 61 |         frequenceOfng = transitionMatrix[ pairToLookFor ] ;
 62 |         // Divide by the currentState to any other.
 63 | 
 64 |         for(auto& [key,val] : transitionMatrix){
 65 | 
 66 |             if( compare(key.first,currentState) ){
 67 |                 sumOther += val; 
 68 |             }
 69 |         }
 70 | 
 71 |     }else{
 72 |         std::cout << "The transition was not found "<< pairToLookFor.first.back() << " " << pairToLookFor.second <<"\n";
 73 |         return -1;
 74 |     }
 75 | 
 76 |     return static_cast<double>(frequenceOfng) / static_cast<double>(sumOther); 
 77 | }
 78 | 
 79 | 
 80 | auto Markov::Chain::storeProbabilities() -> void {
 81 |     
 82 |     if( ! computed_ ){
 83 |         for(const auto& [k,v] : transitionMatrix) {
 84 |             auto prob = transitionProbability(k.second,k.first);
 85 |             probabilities_.push_back( prob );
 86 |         }
 87 |         computed_ = true;
 88 |     }
 89 |     return;
 90 | }
 91 | 
 92 | auto Markov::Chain::generateWord(int length) -> std::string {    
 93 |     
 94 |     this->storeProbabilities();
 95 | 
 96 |     std::vector<double> v;
 97 |     std::random_device rd;
 98 |     std::mt19937 gen(rd());
 99 | 
100 |     for(double& c : probabilities_ ) {
101 |         v.push_back( c*100 );
102 |     }
103 | 
104 |     std::discrete_distribution<> dist( v.begin(), v.end());
105 | 
106 |     std::string res;
107 | 
108 |     for(int n=0; n<length; ++n) {
109 |         auto r = ipMap_[dist(gen)]; 
110 | 
111 |         auto s = std::string(r.second.c_str()) ;
112 | 
113 |         if( "$" != s ){
114 |             res+=s;
115 |         }
116 |         if( "$" != r.first.front()){
117 |             res += " " + r.first.front() + " ";
118 |         }
119 |     }
120 | 
121 |     return res;
122 | }
123 | 
124 | auto Markov::split(std::string str,char delimiter ) -> std::vector<std::string>{
125 | 
126 |     std::vector<std::string> internal;
127 |     std::stringstream ss(str); // Turn the string into a stream.
128 |     std::string tok;
129 |     
130 |     while(getline(ss, tok, delimiter)) {
131 |         internal.push_back(tok);
132 |     }
133 |     
134 |     return internal;
135 | }
136 | 
137 | auto Markov::compare(const Markov::Ngram& lhs,const Markov::Ngram& rhs) -> bool {
138 |     bool areOfEqualWord = true;
139 | 
140 |     if( lhs.size() != rhs.size() ) {
141 |         return false;   
142 |     }
143 | 
144 |     for(int i(0); i< rhs.size() ; ++i){
145 |         if( lhs.at(i) != rhs.at(i) ) {
146 |             areOfEqualWord = false;
147 |             break;
148 |         }
149 |     }
150 | 
151 |     return areOfEqualWord;
152 | }
153 | 
154 | auto Markov::join(Markov::Ngram& ngram) -> std::string {
155 | 
156 |     std::string res;
157 | 
158 |     for(auto& str: ngram){
159 |         res+=str +" ";
160 |     }
161 |     return res;
162 | }
163 | 
164 | int Markov::Chain::incr_{0};
165 | 


--------------------------------------------------------------------------------
/hnnews.txt:
--------------------------------------------------------------------------------
  1 | "I Miss Microsoft Encarta"
  2 | "Information operations directed at Hong Kong"
  3 | "Google OAuth Is Failing with 500 Error Code"
  4 | "Updating our advertising policies on state media"
  5 | "How Rust optimizes async/await"
  6 | "Cerebras Systems unveils a record 1.2T transistor chip for AI"
  7 | "Statement on the Purpose of a Corporation"
  8 | "Performance Matters"
  9 | "Rendering on the Web"
 10 | "OpenDrop: An Open Source AirDrop Implementation"
 11 | "Solitude and Leadership (2010)"
 12 | "SharpScript"
 13 | "Show HN: A little web app for playing around with colors"
 14 | "Every productivity thought I've ever had, as concisely as possible"
 15 | "Wireless Carrier Throttling of Online Video Is Pervasive: Study"
 16 | "Why Did China Just Devalue the Yuan? How Trade Works with Free-Floating Currency"
 17 | "In Amazon’s Bookstore, Orwell Gets a Rewrite"
 18 | "Rules for Intuitive UX"
 19 | "Early Years of Computer Gaming: Steve Russell and Nolan Bushnell (2002) [video]"
 20 | "The Restaurant of Mistaken Orders"
 21 | "Rashomon of Disclosure"
 22 | "Version Museum"
 23 | "Down and Out in the Magic Kingdom (2011)"
 24 | "Traits of Serverless Architecture"
 25 | "Programming as Theory Building (1985) [pdf]"
 26 | "Hacking Image Interpolation for Fun and Profit"
 27 | "Portugal trials use of goats to clear vegetation for reduction of wild fire risk"
 28 | "Mistakes to Avoid When Buying a MicroSD Card (2018)"
 29 | "Handler beliefs affect scent detection dog outcomes (2011)"
 30 | "The World's Largest Submarine: The Soviet Union's Pr. 941 Typhoon SSBN (2014)"
 31 | "Twitter is blocked in China, but its state news agency is buying promoted tweets"
 32 | "How to Build Good Software"
 33 | "A parrot has a question for humans"
 34 | "The Lost City of Heracleion"
 35 | "What is Haberman?"
 36 | "Show HN: Chart.xkcd – Xkcd-styled chart library"
 37 | "Dark Corners and Pitfalls of C++"
 38 | "Nigerian Teens Are Making Sci-Fi Shorts with Slick Visual Effects"
 39 | "“Wealth work” is one of America’s fastest-growing industries"
 40 | "World's largest urban farm to open on a Paris rooftop"
 41 | "Richard Sorge: The Soviet Union’s Master Spy"
 42 | "Show HN: A little web app for playing around with colors"
 43 | "Show HN: Chart.xkcd – Xkcd-styled chart library"
 44 | "Show HN: Crawlab: Open-Source Web Crawler Admin Platform That Runs Any Language"
 45 | "Show HN: Saag as a Service – macronutrient-portioned Indian spinach curry"
 46 | "Show HN: ClojureScript pixel game engine with Blender live-reloading"
 47 | "Show HN: distri: a Linux distribution to research fast package management"
 48 | "Show HN: Add web analytics to a Google Doc in 20 seconds"
 49 | "Show HN: Prophecy.io – Cloud Native Data Engineering"
 50 | "Show HN: Smartip.io – Reliable and Accurate IP Geolocation and Threat API"
 51 | "Show HN: Scenery — Asynchronous communication for teams"
 52 | "Show HN: Pitaya Go, IoT Dev Board with Multiprotocol Wireless Connectivity"
 53 | "Show HN: A marketplace to hire no code experts"
 54 | "Show HN: Register expiring premium domain names for just $99"
 55 | "Show HN: Lazy – Free Bootstrap UI Kit"
 56 | "Show HN: Software jobs with a difference. Filter jobs by interview type"
 57 | "Show HN: Yet another free HTML form to email for your static websites"
 58 | "Show HN: Software Engineering 101"
 59 | "Show HN: A Detailed Look into Scammer Strategy to Steal Your Money – Part 3/3"
 60 | "Show HN: How to Build Community – my 4 years research"
 61 | "Show HN: AlertChimp – Manage prod role, no default permission, elevate on demand""Japanese anime studio Khara moving to Blender"
 62 | "WeWTF"
 63 | "I've reproduced 130 research papers about “predicting the stock market”"
 64 | "How to Build Good Software"
 65 | "Apple will soon treat online web tracking the same as a security vulnerability"
 66 | "A Walk in Hong Kong"
 67 | "OpenDrop: An Open Source AirDrop Implementation"
 68 | "Tech Interview Handbook"
 69 | "Start Your Own ISP"
 70 | "We Have Ruined Childhood"
 71 | "Rails 6.0"
 72 | "Google Employee Writes Memo About ‘The Burden of Being Black at Google’"
 73 | "YAML: Probably not so great after all"
 74 | "Async-std: an async port of the Rust standard library"
 75 | "Big Coal Plants Begin to Close"
 76 | "The most frequent 777 characters give 90% coverage of Kanji in the wild"
 77 | "Every productivity thought I've ever had, as concisely as possible"
 78 | "The Architecture of Open Source Applications"
 79 | "Cool but obscure X11 tools"
 80 | "Japan surpasses China as largest foreign holder of US Treasurys"
 81 | "U.S. Farmers Stung by Tariffs Now Face a $3.5B Corn Loss"
 82 | "The Impact of Meditating Every Day"
 83 | "I Miss Microsoft Encarta"
 84 | "In the US, it's cheaper to build and operate wind farms than buy fossil fuels"
 85 | "Key Negotiation of Bluetooth Attack"
 86 | "Python vs. Rust for Neural Networks"
 87 | "Making email more modern with JMAP"
 88 | "Google Plans to Deprecate FTP URL Support in Chrome"
 89 | "Rules for Intuitive UX"
 90 | "YouTube shuts down music companies’ use of manual copyright claims"
 91 | "Show HN: Chart.xkcd – Xkcd-styled chart library"
 92 | "Nigerian Teens Are Making Sci-Fi Shorts with Slick Visual Effects"
 93 | "Performance Matters"
 94 | "Dirty tricks 6502 programmers use"
 95 | "Open letter from an Android developer to the Google Play team"
 96 | "Media Can’t Stop Presenting Horrifying Stories as ‘Uplifting’ Perseverance Porn"
 97 | "35% Faster Than The Filesystem (2017)"
 98 | "Software architects should be involved in earliest system engineering activities"
 99 | "Why doesn't mathematics collapse, though humans often make mistakes in proofs?"
100 | "Show HN: Saag as a Service – macronutrient-portioned Indian spinach curry"
101 | "NOAA Data Confirms July Was Hottest Month Ever Recorded"
102 | "Nvidia CEO says Google is the only customer building its own silicon at scale"
103 | "Die With Me – A chat app you can only use when you have less than 5% battery"
104 | "Video Game Preservation – An archive of commercial video game source code"
105 | "Alone in the Dark"
106 | "The first solar road has turned out to be a disappointing failure"
107 | "Twitter locked my account for a nine year old tweet"
108 | "Hacking the Sonos IKEA Symfonisk into a High Quality Speaker Amp"
109 | "Twitter is displaying China-made ads attacking Hong Kong protesters"
110 | 


--------------------------------------------------------------------------------