/*
* call-seq:
* solver.simplify_db -> true or false
*
* Deprecated. The same as Solver#simplify.
*
*/
static VALUE solver_simplify_db(VALUE rslv)
{
return solver_simplify(rslv);
}
static lbool solver_search(solver* s, int nof_conflicts,
int nof_learnts)
{
int* levels = s->levels;
double var_decay = 0.95;
double clause_decay = 0.999;
double random_var_freq = 0.02;
int conflictC = 0;
veci learnt_clause;
assert(s->root_level == solver_dlevel(s));
s->stats.starts++;
s->var_decay = (float)(1 / var_decay );
s->cla_decay = (float)(1 / clause_decay);
veci_resize(&s->model,0);
veci_new(&learnt_clause);
for (;;){
clause* confl = solver_propagate(s);
if (confl != 0){
/* CONFLICT */
int blevel;
#ifdef VERBOSEDEBUG
printf(L_IND"**CONFLICT**\n", L_ind);
#endif
s->stats.conflicts++; conflictC++;
if (solver_dlevel(s) == s->root_level){
veci_delete(&learnt_clause);
return l_False;
}
veci_resize(&learnt_clause,0);
solver_analyze(s, confl, &learnt_clause);
blevel = veci_size(&learnt_clause) > 1
? levels[lit_var(veci_begin(&learnt_clause)[1])]
: s->root_level;
blevel = s->root_level > blevel ? s->root_level : blevel;
solver_canceluntil(s,blevel);
solver_record(s,&learnt_clause);
act_var_decay(s);
act_clause_decay(s);
}else{
/* NO CONFLICT */
int next;
if (nof_conflicts >= 0 && conflictC >= nof_conflicts){
/* Reached bound on number of conflicts: */
s->progress_estimate = solver_progress(s);
solver_canceluntil(s,s->root_level);
veci_delete(&learnt_clause);
return l_Undef; }
if (solver_dlevel(s) == 0)
/* Simplify the set of problem clauses: */
solver_simplify(s);
if (nof_learnts >= 0
&& vecp_size(&s->learnts) - s->qtail >= nof_learnts)
/* Reduce the set of learnt clauses: */
solver_reducedb(s);
/* New variable decision: */
s->stats.decisions++;
next = order_select(s,(float)random_var_freq);
if (next == var_Undef){
/* Model found: */
lbool* values = s->assigns;
int i;
for (i = 0; i < s->size; i++)
veci_push(&s->model,(int)values[i]);
solver_canceluntil(s,s->root_level);
veci_delete(&learnt_clause);
/*
veci apa; veci_new(&apa);
for (i = 0; i < s->size; i++)
veci_push(&apa,(int)(s->model.ptr[i] == l_True
? toLit(i) : lit_neg(toLit(i))));
printf("model: ");
printlits((lit*)apa.ptr,
(lit*)apa.ptr + veci_size(&apa)); printf("\n");
veci_delete(&apa);
*/
return l_True;
}
assume(s,lit_neg(toLit(next)));
}
}
#if 0 /* by mao; unreachable code */
return l_Undef; /* cannot happen */
#endif
}
