summaryrefslogtreecommitdiff
path: root/libs/ezsat/ezminisat.cc
blob: b996d4a3dbaf8615c30194dc635adccd5ca3752c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
/*
 *  ezSAT -- A simple and easy to use CNF generator for SAT solvers
 *
 *  Copyright (C) 2013  Clifford Wolf <clifford@clifford.at>
 *  
 *  Permission to use, copy, modify, and/or distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *  
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

// needed for MiniSAT headers (see Minisat Makefile)
#define __STDC_LIMIT_MACROS
#define __STDC_FORMAT_MACROS

#include "ezminisat.h"

#include <limits.h>
#include <stdint.h>
#include <csignal>
#include <cinttypes>
#include <unistd.h>

#include "../minisat/Solver.h"
#include "../minisat/SimpSolver.h"

ezMiniSAT::ezMiniSAT() : minisatSolver(NULL)
{
	minisatSolver = NULL;
	foundContradiction = false;

	freeze(CONST_TRUE);
	freeze(CONST_FALSE);
}

ezMiniSAT::~ezMiniSAT()
{
	if (minisatSolver != NULL)
		delete minisatSolver;
}

void ezMiniSAT::clear()
{
	if (minisatSolver != NULL) {
		delete minisatSolver;
		minisatSolver = NULL;
	}
	foundContradiction = false;
	minisatVars.clear();
#if EZMINISAT_SIMPSOLVER && EZMINISAT_INCREMENTAL
	cnfFrozenVars.clear();
#endif
	ezSAT::clear();
}

#if EZMINISAT_SIMPSOLVER && EZMINISAT_INCREMENTAL
void ezMiniSAT::freeze(int id)
{
	if (!mode_non_incremental())
		cnfFrozenVars.insert(bind(id));
}

bool ezMiniSAT::eliminated(int idx)
{
	idx = idx < 0 ? -idx : idx;
	if (minisatSolver != NULL && idx > 0 && idx <= int(minisatVars.size()))
		return minisatSolver->isEliminated(minisatVars.at(idx-1));
	return false;
}
#endif

#ifndef _WIN32
ezMiniSAT *ezMiniSAT::alarmHandlerThis = NULL;
clock_t ezMiniSAT::alarmHandlerTimeout = 0;

void ezMiniSAT::alarmHandler(int)
{
	if (clock() > alarmHandlerTimeout) {
		alarmHandlerThis->minisatSolver->interrupt();
		alarmHandlerTimeout = 0;
	} else
		alarm(1);
}
#endif

bool ezMiniSAT::solver(const std::vector<int> &modelExpressions, std::vector<bool> &modelValues, const std::vector<int> &assumptions)
{
	preSolverCallback();

	solverTimoutStatus = false;

	if (0) {
contradiction:
		delete minisatSolver;
		minisatSolver = NULL;
		minisatVars.clear();
		foundContradiction = true;
		return false;
	}

	if (foundContradiction) {
		consumeCnf();
		return false;
	}

	std::vector<int> extraClauses, modelIdx;

	for (auto id : assumptions)
		extraClauses.push_back(bind(id));
	for (auto id : modelExpressions)
		modelIdx.push_back(bind(id));

	if (minisatSolver == NULL) {
		minisatSolver = new Solver;
		minisatSolver->verbosity = EZMINISAT_VERBOSITY;
	}

#if EZMINISAT_INCREMENTAL
	std::vector<std::vector<int>> cnf;
	consumeCnf(cnf);
#else
	const std::vector<std::vector<int>> &cnf = this->cnf();
#endif

	while (int(minisatVars.size()) < numCnfVariables())
		minisatVars.push_back(minisatSolver->newVar());

#if EZMINISAT_SIMPSOLVER && EZMINISAT_INCREMENTAL
	for (auto idx : cnfFrozenVars)
		minisatSolver->setFrozen(minisatVars.at(idx > 0 ? idx-1 : -idx-1), true);
	cnfFrozenVars.clear();
#endif

	for (auto &clause : cnf) {
		Minisat::vec<Minisat::Lit> ps;
		for (auto idx : clause) {
			if (idx > 0)
				ps.push(Minisat::mkLit(minisatVars.at(idx-1)));
			else
				ps.push(Minisat::mkLit(minisatVars.at(-idx-1), true));
#if EZMINISAT_SIMPSOLVER
			if (minisatSolver->isEliminated(minisatVars.at(idx > 0 ? idx-1 : -idx-1))) {
				fprintf(stderr, "Assert in %s:%d failed! Missing call to ezsat->freeze(): %s (lit=%d)\n",
						__FILE__, __LINE__, cnfLiteralInfo(idx).c_str(), idx);
				abort();
			}
#endif
		}
		if (!minisatSolver->addClause(ps))
			goto contradiction;
	}

	if (cnf.size() > 0 && !minisatSolver->simplify())
		goto contradiction;

	Minisat::vec<Minisat::Lit> assumps;

	for (auto idx : extraClauses) {
		if (idx > 0)
			assumps.push(Minisat::mkLit(minisatVars.at(idx-1)));
		else
			assumps.push(Minisat::mkLit(minisatVars.at(-idx-1), true));
#if EZMINISAT_SIMPSOLVER
		if (minisatSolver->isEliminated(minisatVars.at(idx > 0 ? idx-1 : -idx-1))) {
			fprintf(stderr, "Assert in %s:%d failed! Missing call to ezsat->freeze(): %s\n", __FILE__, __LINE__, cnfLiteralInfo(idx).c_str());
			abort();
		}
#endif
	}

#ifndef _WIN32
	struct sigaction sig_action;
	struct sigaction old_sig_action;
	int old_alarm_timeout = 0;

	if (solverTimeout > 0) {
		sig_action.sa_handler = alarmHandler;
		sigemptyset(&sig_action.sa_mask);
		sig_action.sa_flags = SA_RESTART;
		alarmHandlerThis = this;
		alarmHandlerTimeout = clock() + solverTimeout*CLOCKS_PER_SEC;
		old_alarm_timeout = alarm(0);
		sigaction(SIGALRM, &sig_action, &old_sig_action);
		alarm(1);
	}
#endif

	bool foundSolution = minisatSolver->solve(assumps);

#ifndef _WIN32
	if (solverTimeout > 0) {
		if (alarmHandlerTimeout == 0)
			solverTimoutStatus = true;
		alarm(0);
		sigaction(SIGALRM, &old_sig_action, NULL);
		alarm(old_alarm_timeout);
	}
#endif

	if (!foundSolution) {
#if !EZMINISAT_INCREMENTAL
		delete minisatSolver;
		minisatSolver = NULL;
		minisatVars.clear();
#endif
		return false;
	}

	modelValues.clear();
	modelValues.resize(modelIdx.size());

	for (size_t i = 0; i < modelIdx.size(); i++)
	{
		int idx = modelIdx[i];
		bool refvalue = true;

		if (idx < 0)
			idx = -idx, refvalue = false;

		using namespace Minisat;
		lbool value = minisatSolver->modelValue(minisatVars.at(idx-1));
		modelValues[i] = (value == Minisat::lbool(refvalue));
	}

#if !EZMINISAT_INCREMENTAL
	delete minisatSolver;
	minisatSolver = NULL;
	minisatVars.clear();
#endif
	return true;
}