├── README
├── kernel.cl
├── main.cc
└── COPYING


/README:
--------------------------------------------------------------------------------
 1 | clsat - OpenCL SAT solver
 2 | -------------------------
 3 | 
 4 | clsat is a small, incomplete, stochastic local search, OpenCL-based SAT
 5 | solver.
 6 | 
 7 | The algorithm is as follows:
 8 |  - Iterate over all the clauses in the instance
 9 |  - Evaluate each clause under the current valuation
10 |  - If a clause is unsatisfied, flip the current value of one of the
11 |    unsatisfied literals
12 |  - Keep going until all the clauses are satisfied
13 | 
14 | The implementation is designed to work well on GPUs, e.g. by having all
15 | threads examine the same clause at the same time, utilising local/shared
16 | memory, eliminating branches, etc.
17 | 
18 | 
19 | Compiling
20 | ---------
21 | 
22 | You need to have the AMD APP SDK installed to compile and run the program.
23 | 
24 |     $ g++ -Wall -g -I<path/to/AMD-APP-SDK>/include -L<path/to/AMD-APP-SDK>/lib/<arch> main.cc -lOpenCL
25 | 
26 | 
27 | To-do
28 | -----
29 | 
30 |  - Split clauses of length > 4 into many smaller clauses
31 |  - Support for XOR clauses
32 |  - Use u32 for literals (we are currently limited to 32,767 variables)
33 |  - Optimisations!
34 |     - Different types may be faster
35 |     - Use vector types/operations if/where possible
36 | 


--------------------------------------------------------------------------------
/kernel.cl:
--------------------------------------------------------------------------------
  1 | /*
  2 |  *  clsat -- OpenCL SAT solver
  3 |  *  Copyright (C) 2011  Vegard Nossum <vegardno@ifi.uio.no>
  4 |  *
  5 |  *  This program is free software; you can redistribute it and/or modify
  6 |  *  it under the terms of the GNU General Public License as published by
  7 |  *  the Free Software Foundation; either version 2 of the License, or
  8 |  *  (at your option) any later version.
  9 |  *
 10 |  *  This program is distributed in the hope that it will be useful,
 11 |  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 12 |  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13 |  *  GNU General Public License for more details.
 14 |  *
 15 |  *  You should have received a copy of the GNU General Public License along
 16 |  *  with this program; if not, write to the Free Software Foundation, Inc.,
 17 |  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 18 |  */
 19 | 
 20 | #define LOCAL_SIZE_0 256
 21 | 
 22 | typedef uchar u8;
 23 | typedef ushort u16;
 24 | typedef uint u32;
 25 | typedef ulong u64;
 26 | 
 27 | struct thread_state {
 28 | 	u32 rnd;
 29 | 	u32 nr_sat_clauses;
 30 | };
 31 | 
 32 | struct clause {
 33 | 	u32 literals[4];
 34 | };
 35 | 
 36 | inline u32 bits(u32 rnd, const unsigned int i, const unsigned int n)
 37 | {
 38 | 	return (rnd >> i) & ((1U << n) - 1);
 39 | }
 40 | 
 41 | u8 get_value(__global u8 *values, u32 lit)
 42 | {
 43 | 	bool sign = lit & 1;
 44 | 	u32 var = lit >> 1;
 45 | 
 46 | 	return values[var * LOCAL_SIZE_0 + get_local_id(0)] ^ sign;
 47 | }
 48 | 
 49 | void set_value(__global u8 *values, u32 lit, u8 value)
 50 | {
 51 | 	bool sign = lit & 1;
 52 | 	u32 var = lit >> 1;
 53 | 
 54 | 	values[var * LOCAL_SIZE_0 + get_local_id(0)] = value ^ sign;
 55 | }
 56 | 
 57 | __kernel void search(__global struct thread_state *states,
 58 | 	__global u8 *values,
 59 | 	unsigned int nr_clauses, __global const struct clause *clauses,
 60 | 	unsigned int clause_i, unsigned int n)
 61 | {
 62 | 	/* Load per-thread state */
 63 | 	struct thread_state state = states[get_global_id(0)];
 64 | 
 65 | 	__local struct clause clause_cache[LOCAL_SIZE_0];
 66 | 	unsigned int clause_cache_i = 0;
 67 | 
 68 | 	/* Initial cache fill; each thread loads a part of the cache from
 69 | 	 * global memory to local memory using a single coalesced transfer
 70 | 	 * as long as each clause is smaller than or equal to 128 bits. */
 71 | 	clause_cache[get_local_id(0)] = clauses[get_local_id(0)];
 72 | 	barrier(CLK_LOCAL_MEM_FENCE);
 73 | 
 74 | 	for (unsigned int i = 0; i < n; ++i) {
 75 | 		/* We use a per-thread pseudo-random number generator. This particular
 76 | 		 * algorithm is REALLY POOR! It doesn't matter so much, however. It is
 77 | 		 * used for tie-breaking in order to prevent us from getting stuck in
 78 | 		 * an infinite loop. It should be really fast, however. */
 79 | 		state.rnd ^= ((state.rnd << 4) | (state.rnd >> 28)) + 0xcafebabe;
 80 | 
 81 | 		struct clause c = clause_cache[clause_cache_i];
 82 | 		u8 v0 = get_value(values, c.literals[0]);
 83 | 		u8 v1 = get_value(values, c.literals[1]);
 84 | 		u8 v2 = get_value(values, c.literals[2]);
 85 | 		u8 v3 = get_value(values, c.literals[3]);
 86 | 		u8 satisfied = v0 | v1 | v2 | v3;
 87 | 
 88 | 		/* Pick an unsatisfied literal to flip (but only if it is not
 89 | 		 * variable 0, which is always false. Each literal is weighted
 90 | 		 * by a random number for tie-breaking between false literals,
 91 | 		 * and the literal with the greatest weight is flipped. */
 92 | 		u8 w0 = (!v0 && c.literals[0]) * (1 + bits(state.rnd,  0, 4));
 93 | 		u8 w1 = (!v1 && c.literals[1]) * (1 + bits(state.rnd,  4, 4));
 94 | 		u8 w2 = (!v2 && c.literals[2]) * (1 + bits(state.rnd,  8, 4));
 95 | 		u8 w3 = (!v3 && c.literals[3]) * (1 + bits(state.rnd, 12, 4));
 96 | 
 97 | 		u8 j = select(0, 1, w0 < w1);
 98 | 		u8 w = max(w0, w1);
 99 | 
100 | 		j = select(j, 2, w < w2);
101 | 		w = max(w, w2);
102 | 
103 | 		j = select(j, 3, w < w3);
104 | 		w = max(w, w3);
105 | 
106 | 		/* Flip the right value. We flip if and only if:
107 | 		 *  1. the clause was not satisfied, AND
108 | 		 *  2. the literal is the chosen unsatisfied literal */
109 | 		/* XXX: We could perhaps be a bit more efficient by retrieving
110 | 		 * the literal's value and the variable's value separately. */
111 | 		set_value(values, c.literals[0], v0 ^ (!satisfied && j == 0));
112 | 		set_value(values, c.literals[1], v1 ^ (!satisfied && j == 1));
113 | 		set_value(values, c.literals[2], v2 ^ (!satisfied && j == 2));
114 | 		set_value(values, c.literals[3], v3 ^ (!satisfied && j == 3));
115 | 
116 | 		/* If the clause was already satisfied, increment nr_sat_clauses;
117 | 		 * otherwise, reset it to 0. */
118 | 		state.nr_sat_clauses = select(0, state.nr_sat_clauses + 1, satisfied);
119 | 
120 | 		/* Refill cache if needed */
121 | 		if (++clause_cache_i == LOCAL_SIZE_0) {
122 | 			clause_cache_i = 0;
123 | 
124 | 			clause_i += get_local_size(0);
125 | 			if (clause_i == nr_clauses)
126 | 				clause_i = 0;
127 | 
128 | 			clause_cache[get_local_id(0)] = clauses[clause_i + get_local_id(0)];
129 | 			barrier(CLK_LOCAL_MEM_FENCE);
130 | 		}
131 | 	}
132 | 
133 | 	/* Write back per-thread state */
134 | 	states[get_global_id(0)] = state;
135 | }
136 | 


--------------------------------------------------------------------------------
/main.cc:
--------------------------------------------------------------------------------
  1 | /*
  2 |  *  clsat -- OpenCL SAT solver
  3 |  *  Copyright (C) 2011  Vegard Nossum <vegardno@ifi.uio.no>
  4 |  *
  5 |  *  This program is free software; you can redistribute it and/or modify
  6 |  *  it under the terms of the GNU General Public License as published by
  7 |  *  the Free Software Foundation; either version 2 of the License, or
  8 |  *  (at your option) any later version.
  9 |  *
 10 |  *  This program is distributed in the hope that it will be useful,
 11 |  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 12 |  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 13 |  *  GNU General Public License for more details.
 14 |  *
 15 |  *  You should have received a copy of the GNU General Public License along
 16 |  *  with this program; if not, write to the Free Software Foundation, Inc.,
 17 |  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 18 |  */
 19 | 
 20 | #include <fstream>
 21 | #include <iostream>
 22 | #include <map>
 23 | #include <set>
 24 | #include <sstream>
 25 | #include <vector>
 26 | 
 27 | #include <sys/mman.h>
 28 | #include <sys/stat.h>
 29 | #include <sys/time.h>
 30 | #include <sys/types.h>
 31 | 
 32 | #include <assert.h>
 33 | #include <fcntl.h>
 34 | #include <stdio.h>
 35 | #include <stdlib.h>
 36 | #include <string.h>
 37 | #include <unistd.h>
 38 | 
 39 | #include <CL/cl.h>
 40 | 
 41 | struct thread_state {
 42 | 	uint32_t rnd;
 43 | 	uint32_t nr_sat_clauses;
 44 | };
 45 | 
 46 | struct gpu_clause {
 47 | 	uint32_t literals[4];
 48 | };
 49 | 
 50 | void CL_CALLBACK pfn_notify(const char *errinfo, const void *private_info, size_t cb, void *user_data)
 51 | {
 52 | 	fprintf(stderr, "notify: %s\n", errinfo);
 53 | }
 54 | 
 55 | typedef int literal;
 56 | typedef unsigned int variable;
 57 | typedef std::map<variable, variable> variable_map;
 58 | typedef std::vector<literal> clause;
 59 | typedef std::vector<clause> clause_vector;
 60 | 
 61 | void read_cnf(const char *filename, variable_map &variables, variable_map &reverse_variables, clause_vector &clauses)
 62 | {
 63 | 	std::ifstream file;
 64 | 
 65 | 	file.open(filename);
 66 | 	if (!file) {
 67 | 		fprintf(stderr, "ifstream::open() failed\n");
 68 | 		exit(EXIT_FAILURE);
 69 | 	}
 70 | 
 71 | 	while (!file.eof()) {
 72 | 		std::string line;
 73 | 		getline(file, line);
 74 | 
 75 | 		if (line.size() == 0)
 76 | 			continue;
 77 | 
 78 | 		/* Skip problem line -- we don't use it anyway */
 79 | 		if (line[0] == 'p')
 80 | 			continue;
 81 | 
 82 | 		/* Skip comments */
 83 | 		if (line[0] == 'c')
 84 | 			continue;
 85 | 
 86 | 		/* XOR clauses */
 87 | 		if (line[0] == 'x') {
 88 | 			fprintf(stderr, "Cannot read XOR clauses\n");
 89 | 			exit(EXIT_FAILURE);
 90 | 		}
 91 | 
 92 | 		clause c;
 93 | 
 94 | 		std::stringstream s(line);
 95 | 		while (!s.eof()) {
 96 | 			literal l;
 97 | 			s >> l;
 98 | 
 99 | 			if (l == 0)
100 | 				break;
101 | 
102 | 			variable v = abs(l);
103 | 
104 | 			/* We remap variables to the range [1, n], where n
105 | 			 * is the total number of variables */
106 | 			variable v2;
107 | 			variable_map::iterator it = variables.find(v);
108 | 			if (it == variables.end()) {
109 | 				v2 = 1 + variables.size();
110 | 				variables[v] = v2;
111 | 				reverse_variables[v2] = v;
112 | 			} else {
113 | 				v2 = it->second;
114 | 			}
115 | 
116 | 			c.push_back(v2 * (l < 0 ? -1 : 1));
117 | 		}
118 | 
119 | 		clauses.push_back(c);
120 | 	}
121 | 
122 | 	file.close();
123 | }
124 | 
125 | int main(int argc, char *argv[])
126 | {
127 | 	/* XXX: Use mersenne twister */
128 | 	srand(time(NULL));
129 | 
130 | 	variable_map variables;
131 | 	variable_map reverse_variables;
132 | 	clause_vector clauses;
133 | 
134 | 	for (int i = 1; i < argc; ++i)
135 | 		read_cnf(argv[i], variables, reverse_variables, clauses);
136 | 
137 | 	cl_uint num_platforms;
138 | 	if (clGetPlatformIDs(0, NULL, &num_platforms) != CL_SUCCESS) {
139 | 		fprintf(stderr, "clGetPlatformIDs() returned failure\n");
140 | 		exit(EXIT_FAILURE);
141 | 	}
142 | 
143 | 	if (num_platforms == 0) {
144 | 		fprintf(stderr, "No OpenCL platforms available\n");
145 | 		exit(EXIT_FAILURE);
146 | 	}
147 | 
148 | 	cl_platform_id platforms[num_platforms];
149 | 	if (clGetPlatformIDs(num_platforms, platforms, NULL) != CL_SUCCESS) {
150 | 		fprintf(stderr, "clGetPlatformIDs() returned failure\n");
151 | 		exit(EXIT_FAILURE);
152 | 	}
153 | 
154 | 	unsigned int platform;
155 | 	for (unsigned int i = 0; i < num_platforms; ++i) {
156 | 		size_t size;
157 | 		if (clGetPlatformInfo(platforms[i], CL_PLATFORM_NAME, 0, NULL, &size)
158 | 			!= CL_SUCCESS)
159 | 		{
160 | 			fprintf(stderr, "clGetPlatformInfo() returned failure\n");
161 | 			continue;
162 | 		}
163 | 
164 | 		char name[size];
165 | 		if (clGetPlatformInfo(platforms[i], CL_PLATFORM_NAME, size, name, 0)
166 | 			!= CL_SUCCESS)
167 | 		{
168 | 			fprintf(stderr, "clGetPlatformInfo() returned failure\n");
169 | 			continue;
170 | 		}
171 | 
172 | 		printf("platform %u: %s\n", i, name);
173 | 
174 | 		platform = i;
175 | 	}
176 | 
177 | 	cl_uint num_devices;
178 | 	if (clGetDeviceIDs(platforms[platform], CL_DEVICE_TYPE_ALL, 0, NULL, &num_devices)
179 | 		!= CL_SUCCESS)
180 | 	{
181 | 		fprintf(stderr, "clGetDeviceIDs() returned failure\n");
182 | 		exit(EXIT_FAILURE);
183 | 	}
184 | 
185 | 	cl_device_id devices[num_devices];
186 | 	if (clGetDeviceIDs(platforms[platform], CL_DEVICE_TYPE_ALL, num_devices, devices, NULL)
187 | 		!= CL_SUCCESS)
188 | 	{
189 | 		fprintf(stderr, "clGetDeviceIDs() returned failure\n");
190 | 		exit(EXIT_FAILURE);
191 | 	}
192 | 
193 | 	unsigned int device;
194 | 	for (unsigned int i = 0; i < num_devices; ++i) {
195 | 		size_t size;
196 | 		if (clGetDeviceInfo(devices[i], CL_DEVICE_NAME, 0, NULL, &size)
197 | 			!= CL_SUCCESS)
198 | 		{
199 | 			fprintf(stderr, "clDeviceInfo() returned failure\n");
200 | 			continue;
201 | 		}
202 | 
203 | 		char name[size];
204 | 		if (clGetDeviceInfo(devices[i], CL_DEVICE_NAME, size, name, NULL)
205 | 			!= CL_SUCCESS)
206 | 		{
207 | 			fprintf(stderr, "clDeviceInfo() returned failure\n");
208 | 			continue;
209 | 		}
210 | 
211 | 		fprintf(stderr, "device %u: %s\n", i, name);
212 | 
213 | 		device = i;
214 | 	}
215 | 
216 | 	cl_int err;
217 | 	cl_context context = clCreateContext(NULL, 1, &devices[device], &pfn_notify, NULL, &err);
218 | 	if (err != CL_SUCCESS) {
219 | 		fprintf(stderr, "clCreateContext() failed\n");
220 | 		exit(EXIT_FAILURE);
221 | 	}
222 | 
223 | 	cl_command_queue queue = clCreateCommandQueue(context, devices[device], 0, &err);
224 | 	if (err != CL_SUCCESS) {
225 | 		fprintf(stderr, "clCreateCommandQueue() failed\n");
226 | 		exit(EXIT_FAILURE);
227 | 	}
228 | 
229 | 	int fd = open("kernel.cl", O_RDONLY);
230 | 	if (fd == -1) {
231 | 		fprintf(stderr, "open() failed\n");
232 | 		exit(EXIT_FAILURE);
233 | 	}
234 | 
235 | 	struct stat st;
236 | 	if (fstat(fd, &st) == -1) {
237 | 		fprintf(stderr, "stat() failed\n");
238 | 		exit(EXIT_FAILURE);
239 | 	}
240 | 
241 | 	void *ptr = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
242 | 	if (ptr == MAP_FAILED) {
243 | 		fprintf(stderr, "mmap() failed\n");
244 | 		exit(EXIT_FAILURE);
245 | 	}
246 | 
247 | 	const char *string = (char *) ptr;
248 | 	const size_t length = st.st_size;
249 | 
250 | 	cl_program program = clCreateProgramWithSource(context, 1, &string, &length, &err);
251 | 	if (err != CL_SUCCESS) {
252 | 		fprintf(stderr, "clCreateProgramWithSource() failed\n");
253 | 		exit(EXIT_FAILURE);
254 | 	}
255 | 
256 | 	if (clBuildProgram(program, 0, NULL, NULL, NULL, NULL) != CL_SUCCESS) {
257 | 		fprintf(stderr, "clBuildProgram() failed\n");
258 | 
259 | 		size_t size;
260 | 		if (clGetProgramBuildInfo(program, devices[device],
261 | 			CL_PROGRAM_BUILD_LOG, 0, NULL, &size) != CL_SUCCESS)
262 | 		{
263 | 			fprintf(stderr, "clGetProgramBuildInfo() failed\n");
264 | 			exit(EXIT_FAILURE);
265 | 		}
266 | 
267 | 		char log[size];
268 | 		if (clGetProgramBuildInfo(program, devices[device],
269 | 			CL_PROGRAM_BUILD_LOG, size, log, NULL) != CL_SUCCESS)
270 | 		{
271 | 			fprintf(stderr, "clGetProgramBuildInfo() failed\n");
272 | 			exit(EXIT_FAILURE);
273 | 		}
274 | 
275 | 		fprintf(stderr, "%s\n", log);
276 | 		exit(EXIT_FAILURE);
277 | 	}
278 | 
279 | 	cl_kernel kernel = clCreateKernel(program, "search", &err);
280 | 	if (err != CL_SUCCESS) {
281 | 		fprintf(stderr, "clCreateKernel() failed\n");
282 | 		exit(EXIT_FAILURE);
283 | 	}
284 | 
285 | 	unsigned int nr_threads = 256;
286 | 
287 | 	struct thread_state *host_threads = new thread_state[nr_threads];
288 | 
289 | 	for (unsigned int i = 0; i < nr_threads; ++i) {
290 | 		host_threads[i].rnd = i;
291 | 		host_threads[i].nr_sat_clauses = 0;
292 | 	}
293 | 
294 | 	cl_mem threads = clCreateBuffer(context, CL_MEM_READ_WRITE | CL_MEM_COPY_HOST_PTR,
295 | 		nr_threads * sizeof(*host_threads), host_threads, &err);
296 | 	if (err != CL_SUCCESS) {
297 | 		fprintf(stderr, "clCreateBuffer() failed\n");
298 | 		exit(EXIT_FAILURE);
299 | 	}
300 | 
301 | 	unsigned int nr_variables = 1 + variables.size();
302 | 
303 | 	uint8_t *host_variables = new uint8_t[nr_variables * nr_threads];
304 | 
305 | 	/* Variable 0 is always false. */
306 | 	for (unsigned int j = 0; j < nr_threads; ++j)
307 | 		host_variables[0 * nr_threads + j] = 0;
308 | 
309 | 	for (unsigned int i = 1; i < nr_variables; ++i) {
310 | 		for (unsigned int j = 0; j < nr_threads; ++j)
311 | 			host_variables[i * nr_threads + j] = rand() % 2;
312 | 	}
313 | 
314 | 	cl_mem values = clCreateBuffer(context, CL_MEM_READ_WRITE | CL_MEM_COPY_HOST_PTR,
315 | 		nr_variables * nr_threads * sizeof(*host_variables), host_variables, &err);
316 | 	if (err != CL_SUCCESS) {
317 | 		fprintf(stderr, "clCreateBuffer() failed\n");
318 | 		exit(EXIT_FAILURE);
319 | 	}
320 | 
321 | 	unsigned int nr_clauses = clauses.size() + nr_threads - (clauses.size() % nr_threads);
322 | 
323 | 	gpu_clause *host_clauses = new gpu_clause[nr_clauses];
324 | 	for (unsigned int i = 0; i < clauses.size(); ++i) {
325 | 		clause &c = clauses[i];
326 | 
327 | 		assert(c.size() >= 1 && c.size() <= 4);
328 | 		for (unsigned int j = 0; j < c.size(); ++j) {
329 | 			literal l = c[j];
330 | 			unsigned int var = abs(l);
331 | 			unsigned int sign = (l < 0);
332 | 
333 | 			host_clauses[i].literals[j] = (var << 1) | sign;
334 | 		}
335 | 
336 | 		/* Fill the rest of the clause with unsatisfied literals */
337 | 		for (unsigned int j = c.size(); j < 4; ++j)
338 | 			host_clauses[i].literals[j] = 0;
339 | 	}
340 | 
341 | 	/* Create trivially true clauses to fill the remaining clause slots. */
342 | 	for (unsigned int i = clauses.size(); i < nr_clauses; ++i) {
343 | 		host_clauses[i].literals[0] = 1;
344 | 		host_clauses[i].literals[1] = 1;
345 | 		host_clauses[i].literals[2] = 1;
346 | 		host_clauses[i].literals[3] = 1;
347 | 	}
348 | 
349 | 	cl_mem device_clauses = clCreateBuffer(context, CL_MEM_READ_WRITE | CL_MEM_COPY_HOST_PTR,
350 | 		nr_clauses * sizeof(*host_clauses), host_clauses, &err);
351 | 	if (err != CL_SUCCESS) {
352 | 		fprintf(stderr, "clCreateBuffer() failed\n");
353 | 		exit(EXIT_FAILURE);
354 | 	}
355 | 
356 | 	unsigned int clause_i = 0;
357 | 	unsigned int n = nr_threads * 256;
358 | 
359 | 	if (clSetKernelArg(kernel, 0, sizeof(threads), &threads) != CL_SUCCESS) {
360 | 		fprintf(stderr, "clSetKernelArg() failed\n");
361 | 		exit(EXIT_FAILURE);
362 | 	}
363 | 
364 | 	if (clSetKernelArg(kernel, 1, sizeof(values), &values) != CL_SUCCESS) {
365 | 		fprintf(stderr, "clSetKernelArg() failed\n");
366 | 		exit(EXIT_FAILURE);
367 | 	}
368 | 
369 | 	/* Number of clauses must be a multiple of nr_threads in order to
370 | 	 * facilitate the shared clause cache. */
371 | 	assert(nr_clauses % nr_threads == 0);
372 | 	if (clSetKernelArg(kernel, 2, sizeof(nr_clauses), &nr_clauses) != CL_SUCCESS) {
373 | 		fprintf(stderr, "clSetKernelArg() failed\n");
374 | 		exit(EXIT_FAILURE);
375 | 	}
376 | 
377 | 	if (clSetKernelArg(kernel, 3, sizeof(device_clauses), &device_clauses) != CL_SUCCESS) {
378 | 		fprintf(stderr, "clSetKernelArg() failed\n");
379 | 		exit(EXIT_FAILURE);
380 | 	}
381 | 
382 | 	/* Number of iterations should be a multiple of nr_threads in order
383 | 	 * to make the best use of the shared clause cache. */
384 | 	assert(n % nr_threads == 0);
385 | 	if (clSetKernelArg(kernel, 5, sizeof(n), &n) != CL_SUCCESS) {
386 | 		fprintf(stderr, "clSetKernelArg() failed\n");
387 | 		exit(EXIT_FAILURE);
388 | 	}
389 | 
390 | 	struct timeval tv_a;
391 | 	if (gettimeofday(&tv_a, NULL) == -1) {
392 | 		fprintf(stderr, "gettimeofday() failed\n");
393 | 		exit(EXIT_FAILURE);
394 | 	}
395 | 
396 | 	size_t global_work_offset = 0;
397 | 	size_t global_work_size = nr_threads;
398 | 	size_t local_work_size = nr_threads;
399 | 
400 | 	while (1) {
401 | 		printf("c clause index: %u/%u\n", clause_i, nr_clauses);
402 | 
403 | 		if (clSetKernelArg(kernel, 4, sizeof(clause_i), &clause_i) != CL_SUCCESS) {
404 | 			fprintf(stderr, "clSetKernelArg() failed\n");
405 | 			exit(EXIT_FAILURE);
406 | 		}
407 | 
408 | 		if ((err = clEnqueueNDRangeKernel(queue, kernel, 1,
409 | 			&global_work_offset,
410 | 			&global_work_size,
411 | 			&local_work_size,
412 | 			0, NULL, NULL)) != CL_SUCCESS)
413 | 		{
414 | 			printf("%d\n", err);
415 | 
416 | 			fprintf(stderr, "clEnqueue() failed\n");
417 | 			exit(EXIT_FAILURE);
418 | 		}
419 | 
420 | 		if (clEnqueueReadBuffer(queue, threads, CL_TRUE, 0,
421 | 			nr_threads * sizeof(*host_threads), host_threads, 0, NULL, NULL) != CL_SUCCESS)
422 | 		{
423 | 			fprintf(stderr, "clEnqueueReadBuffer() failed\n");
424 | 			exit(EXIT_FAILURE);
425 | 		}
426 | 
427 | 		if (clFinish(queue) != CL_SUCCESS) {
428 | 			fprintf(stderr, "clFinish() failed\n");
429 | 			exit(EXIT_FAILURE);
430 | 		}
431 | 
432 | 		bool found_solution = false;
433 | 		unsigned int max_nr_sat_clauses = 0;
434 | 
435 | 		for (unsigned int i = 0; i < nr_threads; ++i) {
436 | 			unsigned int nr_sat_clauses = host_threads[i].nr_sat_clauses;
437 | 
438 | 			if (nr_sat_clauses > max_nr_sat_clauses)
439 | 				max_nr_sat_clauses = nr_sat_clauses;
440 | 
441 | 			if (nr_sat_clauses < nr_clauses)
442 | 				continue;
443 | 
444 | 			if (!found_solution) {
445 | 				/* Fetch all the threads' current valuations
446 | 				 * if we didn't already */
447 | 				if (clEnqueueReadBuffer(queue, values, CL_TRUE, 0,
448 | 					nr_threads * nr_variables * sizeof(*host_variables),
449 | 					host_variables, 0, NULL, NULL) != CL_SUCCESS)
450 | 				{
451 | 					fprintf(stderr, "clEnqueueReadBuffer() failed\n");
452 | 					exit(EXIT_FAILURE);
453 | 				}
454 | 
455 | 				if (clFinish(queue) != CL_SUCCESS) {
456 | 					fprintf(stderr, "clFinish() failed\n");
457 | 					exit(EXIT_FAILURE);
458 | 				}
459 | 			}
460 | 
461 | 			/* We have a solution! */
462 | 			found_solution = true;
463 | 
464 | 			/* Double-check on the host that this is a correct solution. */
465 | 			for (unsigned int j = 0; j < clauses.size(); ++j) {
466 | 				clause &c = clauses[j];
467 | 
468 | 				bool value = false;
469 | 				for (unsigned int k = 0; k < c.size(); ++k) {
470 | 					literal l = c[k];
471 | 					unsigned int var = abs(l);
472 | 					unsigned int sign = (l < 0);
473 | 
474 | 					value |= host_variables[var * nr_threads + i] ^ sign;
475 | 				}
476 | 
477 | 				assert(value);
478 | 			}
479 | 
480 | 			printf("v");
481 | 			for (unsigned int j = 1; j < nr_variables; ++j) {
482 | 				unsigned int v = reverse_variables[j];
483 | 				printf(" %d", host_variables[j * nr_threads + i] ? v : -v);
484 | 			}
485 | 
486 | 			printf("\n");
487 | 		}
488 | 
489 | 		if (found_solution)
490 | 			break;
491 | 
492 | 		printf("c best: %u\n", max_nr_sat_clauses);
493 | 
494 | 		clause_i = (clause_i + n) % nr_clauses;
495 | 	}
496 | 
497 | 	struct timeval tv_b;
498 | 	if (gettimeofday(&tv_b, NULL) == -1) {
499 | 		fprintf(stderr, "gettimeofday() failed\n");
500 | 		exit(EXIT_FAILURE);
501 | 	}
502 | 
503 | 	struct timeval tv_delta;
504 | 	timersub(&tv_b, &tv_a, &tv_delta);
505 | 	fprintf(stderr, "c Wall time: %lu.%06lu\n", tv_delta.tv_sec, tv_delta.tv_usec);
506 | 
507 | 	delete[] host_threads;
508 | 	delete[] host_variables;
509 | 	delete[] host_clauses;
510 | 
511 | 	clReleaseMemObject(threads);
512 | 	clReleaseMemObject(values);
513 | 	clReleaseMemObject(device_clauses);
514 | 
515 | 	clReleaseKernel(kernel);
516 | 	clReleaseProgram(program);
517 | 	clReleaseCommandQueue(queue);
518 | 	clReleaseContext(context);
519 | 
520 | 	return 0;
521 | }
522 | 


--------------------------------------------------------------------------------
/COPYING:
--------------------------------------------------------------------------------
  1 |                     GNU GENERAL PUBLIC LICENSE
  2 |                        Version 2, June 1991
  3 | 
  4 |  Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
  5 |  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  6 |  Everyone is permitted to copy and distribute verbatim copies
  7 |  of this license document, but changing it is not allowed.
  8 | 
  9 |                             Preamble
 10 | 
 11 |   The licenses for most software are designed to take away your
 12 | freedom to share and change it.  By contrast, the GNU General Public
 13 | License is intended to guarantee your freedom to share and change free
 14 | software--to make sure the software is free for all its users.  This
 15 | General Public License applies to most of the Free Software
 16 | Foundation's software and to any other program whose authors commit to
 17 | using it.  (Some other Free Software Foundation software is covered by
 18 | the GNU Lesser General Public License instead.)  You can apply it to
 19 | your programs, too.
 20 | 
 21 |   When we speak of free software, we are referring to freedom, not
 22 | price.  Our General Public Licenses are designed to make sure that you
 23 | have the freedom to distribute copies of free software (and charge for
 24 | this service if you wish), that you receive source code or can get it
 25 | if you want it, that you can change the software or use pieces of it
 26 | in new free programs; and that you know you can do these things.
 27 | 
 28 |   To protect your rights, we need to make restrictions that forbid
 29 | anyone to deny you these rights or to ask you to surrender the rights.
 30 | These restrictions translate to certain responsibilities for you if you
 31 | distribute copies of the software, or if you modify it.
 32 | 
 33 |   For example, if you distribute copies of such a program, whether
 34 | gratis or for a fee, you must give the recipients all the rights that
 35 | you have.  You must make sure that they, too, receive or can get the
 36 | source code.  And you must show them these terms so they know their
 37 | rights.
 38 | 
 39 |   We protect your rights with two steps: (1) copyright the software, and
 40 | (2) offer you this license which gives you legal permission to copy,
 41 | distribute and/or modify the software.
 42 | 
 43 |   Also, for each author's protection and ours, we want to make certain
 44 | that everyone understands that there is no warranty for this free
 45 | software.  If the software is modified by someone else and passed on, we
 46 | want its recipients to know that what they have is not the original, so
 47 | that any problems introduced by others will not reflect on the original
 48 | authors' reputations.
 49 | 
 50 |   Finally, any free program is threatened constantly by software
 51 | patents.  We wish to avoid the danger that redistributors of a free
 52 | program will individually obtain patent licenses, in effect making the
 53 | program proprietary.  To prevent this, we have made it clear that any
 54 | patent must be licensed for everyone's free use or not licensed at all.
 55 | 
 56 |   The precise terms and conditions for copying, distribution and
 57 | modification follow.
 58 | 
 59 |                     GNU GENERAL PUBLIC LICENSE
 60 |    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 61 | 
 62 |   0. This License applies to any program or other work which contains
 63 | a notice placed by the copyright holder saying it may be distributed
 64 | under the terms of this General Public License.  The "Program", below,
 65 | refers to any such program or work, and a "work based on the Program"
 66 | means either the Program or any derivative work under copyright law:
 67 | that is to say, a work containing the Program or a portion of it,
 68 | either verbatim or with modifications and/or translated into another
 69 | language.  (Hereinafter, translation is included without limitation in
 70 | the term "modification".)  Each licensee is addressed as "you".
 71 | 
 72 | Activities other than copying, distribution and modification are not
 73 | covered by this License; they are outside its scope.  The act of
 74 | running the Program is not restricted, and the output from the Program
 75 | is covered only if its contents constitute a work based on the
 76 | Program (independent of having been made by running the Program).
 77 | Whether that is true depends on what the Program does.
 78 | 
 79 |   1. You may copy and distribute verbatim copies of the Program's
 80 | source code as you receive it, in any medium, provided that you
 81 | conspicuously and appropriately publish on each copy an appropriate
 82 | copyright notice and disclaimer of warranty; keep intact all the
 83 | notices that refer to this License and to the absence of any warranty;
 84 | and give any other recipients of the Program a copy of this License
 85 | along with the Program.
 86 | 
 87 | You may charge a fee for the physical act of transferring a copy, and
 88 | you may at your option offer warranty protection in exchange for a fee.
 89 | 
 90 |   2. You may modify your copy or copies of the Program or any portion
 91 | of it, thus forming a work based on the Program, and copy and
 92 | distribute such modifications or work under the terms of Section 1
 93 | above, provided that you also meet all of these conditions:
 94 | 
 95 |     a) You must cause the modified files to carry prominent notices
 96 |     stating that you changed the files and the date of any change.
 97 | 
 98 |     b) You must cause any work that you distribute or publish, that in
 99 |     whole or in part contains or is derived from the Program or any
100 |     part thereof, to be licensed as a whole at no charge to all third
101 |     parties under the terms of this License.
102 | 
103 |     c) If the modified program normally reads commands interactively
104 |     when run, you must cause it, when started running for such
105 |     interactive use in the most ordinary way, to print or display an
106 |     announcement including an appropriate copyright notice and a
107 |     notice that there is no warranty (or else, saying that you provide
108 |     a warranty) and that users may redistribute the program under
109 |     these conditions, and telling the user how to view a copy of this
110 |     License.  (Exception: if the Program itself is interactive but
111 |     does not normally print such an announcement, your work based on
112 |     the Program is not required to print an announcement.)
113 | 
114 | These requirements apply to the modified work as a whole.  If
115 | identifiable sections of that work are not derived from the Program,
116 | and can be reasonably considered independent and separate works in
117 | themselves, then this License, and its terms, do not apply to those
118 | sections when you distribute them as separate works.  But when you
119 | distribute the same sections as part of a whole which is a work based
120 | on the Program, the distribution of the whole must be on the terms of
121 | this License, whose permissions for other licensees extend to the
122 | entire whole, and thus to each and every part regardless of who wrote it.
123 | 
124 | Thus, it is not the intent of this section to claim rights or contest
125 | your rights to work written entirely by you; rather, the intent is to
126 | exercise the right to control the distribution of derivative or
127 | collective works based on the Program.
128 | 
129 | In addition, mere aggregation of another work not based on the Program
130 | with the Program (or with a work based on the Program) on a volume of
131 | a storage or distribution medium does not bring the other work under
132 | the scope of this License.
133 | 
134 |   3. You may copy and distribute the Program (or a work based on it,
135 | under Section 2) in object code or executable form under the terms of
136 | Sections 1 and 2 above provided that you also do one of the following:
137 | 
138 |     a) Accompany it with the complete corresponding machine-readable
139 |     source code, which must be distributed under the terms of Sections
140 |     1 and 2 above on a medium customarily used for software interchange; or,
141 | 
142 |     b) Accompany it with a written offer, valid for at least three
143 |     years, to give any third party, for a charge no more than your
144 |     cost of physically performing source distribution, a complete
145 |     machine-readable copy of the corresponding source code, to be
146 |     distributed under the terms of Sections 1 and 2 above on a medium
147 |     customarily used for software interchange; or,
148 | 
149 |     c) Accompany it with the information you received as to the offer
150 |     to distribute corresponding source code.  (This alternative is
151 |     allowed only for noncommercial distribution and only if you
152 |     received the program in object code or executable form with such
153 |     an offer, in accord with Subsection b above.)
154 | 
155 | The source code for a work means the preferred form of the work for
156 | making modifications to it.  For an executable work, complete source
157 | code means all the source code for all modules it contains, plus any
158 | associated interface definition files, plus the scripts used to
159 | control compilation and installation of the executable.  However, as a
160 | special exception, the source code distributed need not include
161 | anything that is normally distributed (in either source or binary
162 | form) with the major components (compiler, kernel, and so on) of the
163 | operating system on which the executable runs, unless that component
164 | itself accompanies the executable.
165 | 
166 | If distribution of executable or object code is made by offering
167 | access to copy from a designated place, then offering equivalent
168 | access to copy the source code from the same place counts as
169 | distribution of the source code, even though third parties are not
170 | compelled to copy the source along with the object code.
171 | 
172 |   4. You may not copy, modify, sublicense, or distribute the Program
173 | except as expressly provided under this License.  Any attempt
174 | otherwise to copy, modify, sublicense or distribute the Program is
175 | void, and will automatically terminate your rights under this License.
176 | However, parties who have received copies, or rights, from you under
177 | this License will not have their licenses terminated so long as such
178 | parties remain in full compliance.
179 | 
180 |   5. You are not required to accept this License, since you have not
181 | signed it.  However, nothing else grants you permission to modify or
182 | distribute the Program or its derivative works.  These actions are
183 | prohibited by law if you do not accept this License.  Therefore, by
184 | modifying or distributing the Program (or any work based on the
185 | Program), you indicate your acceptance of this License to do so, and
186 | all its terms and conditions for copying, distributing or modifying
187 | the Program or works based on it.
188 | 
189 |   6. Each time you redistribute the Program (or any work based on the
190 | Program), the recipient automatically receives a license from the
191 | original licensor to copy, distribute or modify the Program subject to
192 | these terms and conditions.  You may not impose any further
193 | restrictions on the recipients' exercise of the rights granted herein.
194 | You are not responsible for enforcing compliance by third parties to
195 | this License.
196 | 
197 |   7. If, as a consequence of a court judgment or allegation of patent
198 | infringement or for any other reason (not limited to patent issues),
199 | conditions are imposed on you (whether by court order, agreement or
200 | otherwise) that contradict the conditions of this License, they do not
201 | excuse you from the conditions of this License.  If you cannot
202 | distribute so as to satisfy simultaneously your obligations under this
203 | License and any other pertinent obligations, then as a consequence you
204 | may not distribute the Program at all.  For example, if a patent
205 | license would not permit royalty-free redistribution of the Program by
206 | all those who receive copies directly or indirectly through you, then
207 | the only way you could satisfy both it and this License would be to
208 | refrain entirely from distribution of the Program.
209 | 
210 | If any portion of this section is held invalid or unenforceable under
211 | any particular circumstance, the balance of the section is intended to
212 | apply and the section as a whole is intended to apply in other
213 | circumstances.
214 | 
215 | It is not the purpose of this section to induce you to infringe any
216 | patents or other property right claims or to contest validity of any
217 | such claims; this section has the sole purpose of protecting the
218 | integrity of the free software distribution system, which is
219 | implemented by public license practices.  Many people have made
220 | generous contributions to the wide range of software distributed
221 | through that system in reliance on consistent application of that
222 | system; it is up to the author/donor to decide if he or she is willing
223 | to distribute software through any other system and a licensee cannot
224 | impose that choice.
225 | 
226 | This section is intended to make thoroughly clear what is believed to
227 | be a consequence of the rest of this License.
228 | 
229 |   8. If the distribution and/or use of the Program is restricted in
230 | certain countries either by patents or by copyrighted interfaces, the
231 | original copyright holder who places the Program under this License
232 | may add an explicit geographical distribution limitation excluding
233 | those countries, so that distribution is permitted only in or among
234 | countries not thus excluded.  In such case, this License incorporates
235 | the limitation as if written in the body of this License.
236 | 
237 |   9. The Free Software Foundation may publish revised and/or new versions
238 | of the General Public License from time to time.  Such new versions will
239 | be similar in spirit to the present version, but may differ in detail to
240 | address new problems or concerns.
241 | 
242 | Each version is given a distinguishing version number.  If the Program
243 | specifies a version number of this License which applies to it and "any
244 | later version", you have the option of following the terms and conditions
245 | either of that version or of any later version published by the Free
246 | Software Foundation.  If the Program does not specify a version number of
247 | this License, you may choose any version ever published by the Free Software
248 | Foundation.
249 | 
250 |   10. If you wish to incorporate parts of the Program into other free
251 | programs whose distribution conditions are different, write to the author
252 | to ask for permission.  For software which is copyrighted by the Free
253 | Software Foundation, write to the Free Software Foundation; we sometimes
254 | make exceptions for this.  Our decision will be guided by the two goals
255 | of preserving the free status of all derivatives of our free software and
256 | of promoting the sharing and reuse of software generally.
257 | 
258 |                             NO WARRANTY
259 | 
260 |   11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
261 | FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
262 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
263 | PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
264 | OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
265 | MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
266 | TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
267 | PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
268 | REPAIR OR CORRECTION.
269 | 
270 |   12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
271 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
272 | REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
273 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
274 | OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
275 | TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
276 | YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
277 | PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
278 | POSSIBILITY OF SUCH DAMAGES.
279 | 
280 |                      END OF TERMS AND CONDITIONS
281 | 
282 |             How to Apply These Terms to Your New Programs
283 | 
284 |   If you develop a new program, and you want it to be of the greatest
285 | possible use to the public, the best way to achieve this is to make it
286 | free software which everyone can redistribute and change under these terms.
287 | 
288 |   To do so, attach the following notices to the program.  It is safest
289 | to attach them to the start of each source file to most effectively
290 | convey the exclusion of warranty; and each file should have at least
291 | the "copyright" line and a pointer to where the full notice is found.
292 | 
293 |     <one line to give the program's name and a brief idea of what it does.>
294 |     Copyright (C) <year>  <name of author>
295 | 
296 |     This program is free software; you can redistribute it and/or modify
297 |     it under the terms of the GNU General Public License as published by
298 |     the Free Software Foundation; either version 2 of the License, or
299 |     (at your option) any later version.
300 | 
301 |     This program is distributed in the hope that it will be useful,
302 |     but WITHOUT ANY WARRANTY; without even the implied warranty of
303 |     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
304 |     GNU General Public License for more details.
305 | 
306 |     You should have received a copy of the GNU General Public License along
307 |     with this program; if not, write to the Free Software Foundation, Inc.,
308 |     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
309 | 
310 | Also add information on how to contact you by electronic and paper mail.
311 | 
312 | If the program is interactive, make it output a short notice like this
313 | when it starts in an interactive mode:
314 | 
315 |     Gnomovision version 69, Copyright (C) year name of author
316 |     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
317 |     This is free software, and you are welcome to redistribute it
318 |     under certain conditions; type `show c' for details.
319 | 
320 | The hypothetical commands `show w' and `show c' should show the appropriate
321 | parts of the General Public License.  Of course, the commands you use may
322 | be called something other than `show w' and `show c'; they could even be
323 | mouse-clicks or menu items--whatever suits your program.
324 | 
325 | You should also get your employer (if you work as a programmer) or your
326 | school, if any, to sign a "copyright disclaimer" for the program, if
327 | necessary.  Here is a sample; alter the names:
328 | 
329 |   Yoyodyne, Inc., hereby disclaims all copyright interest in the program
330 |   `Gnomovision' (which makes passes at compilers) written by James Hacker.
331 | 
332 |   <signature of Ty Coon>, 1 April 1989
333 |   Ty Coon, President of Vice
334 | 
335 | This General Public License does not permit incorporating your program into
336 | proprietary programs.  If your program is a subroutine library, you may
337 | consider it more useful to permit linking proprietary applications with the
338 | library.  If this is what you want to do, use the GNU Lesser General
339 | Public License instead of this License.
340 | 


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