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minisat/Main.C

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/******************************************************************************************[Main.C]
MiniSat -- Copyright (c) 2003-2005, Niklas Een, Niklas Sorensson
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
**************************************************************************************************/
#include "Solver.h"
#include <ctime>
#include <unistd.h>
#include <signal.h>
#include <zlib.h>
//=================================================================================================
// BCNF Parser:
#define CHUNK_LIMIT 1048576
static void parse_BCNF(cchar* filename, Solver& S)
{
FILE* in = fopen(filename, "rb");
if (in == NULL) fprintf(stderr, "ERROR! Could not open file: %s\n", filename), exit(1);
char header[16];
fread(header, 1, 16, in);
if (strncmp(header, "BCNF", 4) != 0) fprintf(stderr, "ERROR! Not a BCNF file: %s\n", filename), exit(1);
if (*(int*)(header+4) != 0x01020304) fprintf(stderr, "ERROR! BCNF file in unsupported byte-order: %s\n", filename), exit(1);
int n_vars = *(int*)(header+ 8);
//int n_clauses = *(int*)(header+12);
int* buf = xmalloc<int>(CHUNK_LIMIT);
int buf_sz;
vec<Lit> c;
for (int i = 0; i < n_vars; i++) S.newVar();
for(;;){
int n = fread(&buf_sz, 4, 1, in);
if (n != 1) break;
assert(buf_sz <= CHUNK_LIMIT);
fread(buf, 4, buf_sz, in);
int* p = buf;
while (*p != -1){
int size = *p++;
c.clear();
c.growTo(size);
for (int i = 0; i < size; i++)
c[i] = toLit(p[i]);
p += size;
S.addClause(c); // Add clause.
if (!S.okay()){
xfree(buf); fclose(in);
return; }
}
}
xfree(buf);
fclose(in);
}
//=================================================================================================
// DIMACS Parser:
class StreamBuffer {
gzFile in;
char buf[CHUNK_LIMIT];
int pos;
int size;
void assureLookahead() {
if (pos >= size) {
pos = 0;
size = gzread(in, buf, sizeof(buf)); } }
public:
StreamBuffer(gzFile i) : in(i), pos(0), size(0) {
assureLookahead(); }
int operator * () { return (pos >= size) ? EOF : buf[pos]; }
void operator ++ () { pos++; assureLookahead(); }
};
//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
template<class B>
static void skipWhitespace(B& in) {
while ((*in >= 9 && *in <= 13) || *in == 32)
++in; }
template<class B>
static void skipLine(B& in) {
for (;;){
if (*in == EOF) return;
if (*in == '\n') { ++in; return; }
++in; } }
template<class B>
static int parseInt(B& in) {
int val = 0;
bool neg = false;
skipWhitespace(in);
if (*in == '-') neg = true, ++in;
else if (*in == '+') ++in;
if (*in < '0' || *in > '9') fprintf(stderr, "PARSE ERROR! Unexpected char: %c\n", *in), exit(3);
while (*in >= '0' && *in <= '9')
val = val*10 + (*in - '0'),
++in;
return neg ? -val : val; }
template<class B>
static void readClause(B& in, Solver& S, vec<Lit>& lits) {
int parsed_lit, var;
lits.clear();
for (;;){
parsed_lit = parseInt(in);
if (parsed_lit == 0) break;
var = abs(parsed_lit)-1;
while (var >= S.nVars()) S.newVar();
lits.push( (parsed_lit > 0) ? Lit(var) : ~Lit(var) );
}
}
template<class B>
static void parse_DIMACS_main(B& in, Solver& S) {
vec<Lit> lits;
for (;;){
skipWhitespace(in);
if (*in == EOF)
break;
else if (*in == 'c' || *in == 'p')
skipLine(in);
else
readClause(in, S, lits),
S.addClause(lits);
}
}
// Inserts problem into solver.
//
static void parse_DIMACS(gzFile input_stream, Solver& S) {
StreamBuffer in(input_stream);
parse_DIMACS_main(in, S); }
//=================================================================================================
void printStats(SolverStats& stats)
{
double cpu_time = cpuTime();
int64 mem_used = memUsed();
reportf("restarts : %"I64_fmt"\n", stats.starts);
reportf("conflicts : %-12"I64_fmt" (%.0f /sec)\n", stats.conflicts , stats.conflicts /cpu_time);
reportf("decisions : %-12"I64_fmt" (%.0f /sec)\n", stats.decisions , stats.decisions /cpu_time);
reportf("propagations : %-12"I64_fmt" (%.0f /sec)\n", stats.propagations, stats.propagations/cpu_time);
reportf("conflict literals : %-12"I64_fmt" (%4.2f %% deleted)\n", stats.tot_literals, (stats.max_literals - stats.tot_literals)*100 / (double)stats.max_literals);
if (mem_used != 0) reportf("Memory used : %.2f MB\n", mem_used / 1048576.0);
reportf("CPU time : %g s\n", cpu_time);
}
Solver* solver;
static void SIGINT_handler(int signum) {
reportf("\n"); reportf("*** INTERRUPTED ***\n");
printStats(solver->stats);
reportf("\n"); reportf("*** INTERRUPTED ***\n");
exit(1); }
//=================================================================================================
// Simplistic proof-checker -- just to illustrate the use of 'ProofTraverser':
#include "Sort.h"
static void resolve(vec<Lit>& main, vec<Lit>& other, Var x)
{
Lit p;
bool ok1 = false, ok2 = false;
for (int i = 0; i < main.size(); i++){
if (var(main[i]) == x){
ok1 = true, p = main[i];
main[i] = main.last();
main.pop();
break;
}
}
for (int i = 0; i < other.size(); i++){
if (var(other[i]) != x)
main.push(other[i]);
else{
if (p != ~other[i])
printf("PROOF ERROR! Resolved on variable with SAME polarity in both clauses: %d\n", x+1);
ok2 = true;
}
}
if (!ok1 || !ok2)
printf("PROOF ERROR! Resolved on missing variable: %d\n", x+1);
sortUnique(main);
}
struct Checker : public ProofTraverser {
vec<vec<Lit> > clauses;
void root (const vec<Lit>& c) {
//**/printf("%d: ROOT", clauses.size()); for (int i = 0; i < c.size(); i++) printf(" %s%d", sign(c[i])?"-":"", var(c[i])+1); printf("\n");
clauses.push();
c.copyTo(clauses.last()); }
void chain (const vec<ClauseId>& cs, const vec<Var>& xs) {
//**/printf("%d: CHAIN %d", clauses.size(), cs[0]); for (int i = 0; i < xs.size(); i++) printf(" [%d] %d", xs[i]+1, cs[i+1]);
clauses.push();
vec<Lit>& c = clauses.last();
clauses[cs[0]].copyTo(c);
for (int i = 0; i < xs.size(); i++)
resolve(c, clauses[cs[i+1]], xs[i]);
//**/printf(" =>"); for (int i = 0; i < c.size(); i++) printf(" %s%d", sign(c[i])?"-":"", var(c[i])+1); printf("\n");
}
void deleted(ClauseId c) {
clauses[c].clear(); }
};
void checkProof(Proof* proof, ClauseId goal = ClauseId_NULL)
{
Checker trav;
proof->traverse(trav, goal);
vec<Lit>& c = trav.clauses.last();
printf("Final clause:");
if (c.size() == 0)
printf(" <empty>\n");
else{
for (int i = 0; i < c.size(); i++)
printf(" %s%d", sign(c[i])?"-":"", var(c[i])+1);
printf("\n");
}
}
//=================================================================================================
// Main:
static const char* doc =
"USAGE: minisat <input-file> [options]\n"
" -r <result file> Write result (the word \"SAT\" plus model, or just \"UNSAT\") to file.\n"
" -p <proof trace> Write the proof trace to this file.\n"
" -c Check the proof trace by simple (read \"slow\") proof checker.\n"
;
int main(int argc, char** argv)
{
char* input = NULL;
char* result = NULL;
char* proof = NULL;
bool check = false;
// Parse options:
//
for (int i = 1; i < argc; i++){
if (argv[i][0] != '-'){
if (input != NULL)
fprintf(stderr, "ERROR! Only one input file may be specified.\n"), exit(1);
input = argv[i];
}else{
switch (argv[i][1]){
case 'r':
i++; if (i >= argc) fprintf(stderr, "ERROR! Missing filename after '-r' option.\n");
result = argv[i];
break;
case 'p':
i++; if (i >= argc) fprintf(stderr, "ERROR! Missing filename after '-p' option.\n");
proof = argv[i];
break;
case 'c':
check = true;
break;
case 'h':
reportf("%s", doc);
exit(0);
default:
fprintf(stderr, "ERROR! Invalid option: %s\n", argv[i]), exit(1);
}
}
}
// Parse input and perform SAT:
//
Solver S;
if (proof != NULL || check)
S.proof = new Proof();
if (input != NULL && strlen(input) >= 5 && strcmp(&input[strlen(input)-5], ".bcnf") == 0)
parse_BCNF(input, S);
else{
if (input == NULL)
reportf("Reading from standard input... Use '-h' for help.\n");
gzFile in = (input == NULL) ? gzdopen(0, "rb") : gzopen(input, "rb");
if (in == NULL)
fprintf(stderr, "ERROR! Could not open file: %s\n", (input == NULL) ? "<stdin>" : input), exit(1);
parse_DIMACS(in, S);
gzclose(in);
}
FILE* res = (result != NULL) ? fopen(result, "wb") : NULL;
if (!S.okay()){
if (res != NULL) fprintf(res, "UNSAT\n"), fclose(res);
if (S.proof != NULL && proof != NULL) S.proof->save(proof);
if (S.proof != NULL && check) printf("Checking proof...\n"), checkProof(S.proof);
reportf("Trivial problem\n");
reportf("UNSATISFIABLE\n");
exit(20);
}
S.verbosity = 1;
solver = &S;
signal(SIGINT,SIGINT_handler);
signal(SIGHUP,SIGINT_handler);
S.solve();
printStats(S.stats);
reportf("\n");
reportf(S.okay() ? "SATISFIABLE\n" : "UNSATISFIABLE\n");
if (res != NULL){
if (S.okay()){
fprintf(res, "SAT\n");
for (int i = 0; i < S.nVars(); i++)
if (S.model[i] != l_Undef)
fprintf(res, "%s%s%d", (i==0)?"":" ", (S.model[i]==l_True)?"":"-", i+1);
fprintf(res, " 0\n");
}else
fprintf(res, "UNSAT\n");
fclose(res);
}
if (S.proof != NULL && !S.okay()){
if (proof != NULL)
S.proof->save(proof);
if (check)
printf("Checking proof...\n"),
checkProof(S.proof);
}
exit(S.okay() ? 10 : 20); // (faster than "return", which will invoke the destructor for 'Solver')
}
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