/*
* Assert all the conditions from prob into ctx
* - return the internalization code
*/
static int32_t exists_context_assert_conditions(ef_solver_t *solver) {
context_t *ctx;
uint32_t n;
ctx = solver->exists_context;
assert(ctx != NULL && context_status(ctx) == STATUS_IDLE);
n = ef_prob_num_conditions(solver->prob);
return assert_formulas(ctx, n, solver->prob->conditions);
}
/*
* Sample exists models
* - stop when we find one that's not refuted by the forall constraints
* - or when we reach the iteration bound
*
* Result:
* - solver->status = EF_STATUS_ERROR if something goes wrong
* - solver->status = EF_STATUS_INTERRUPTED if one of the calls to
* check_context is interrupted
* - solver->status = EF_STATUS_UNSAT if all efmodels have been tried and none
* of them worked
* - solver->status = EF_STATUS_UNKNOWN if the iteration limit is reached
* - solver->status = EF_STATUS_SAT if a good model is found
*
* In the later case,
* - the model is stored in solver->exists_model
* - also it's available as a mapping form solver->prob->evars to solver->evalues
*
* Also solver->iters stores the number of iterations used.
*/
static void ef_solver_search(ef_solver_t *solver) {
smt_status_t stat;
uint32_t i, max;
max = solver->max_iters;
i = 0;
assert(max > 0);
tprintf(solver->trace, 2,
"(EF search: %"PRIu32" constraints, %"PRIu32" exists vars, %"PRIu32" forall vars)\n",
ef_prob_num_constraints(solver->prob),
ef_prob_num_evars(solver->prob),
ef_prob_num_uvars(solver->prob));
#if EF_VERBOSE
printf("\nConditions on the exists variables:\n");
yices_pp_term_array(stdout, ef_prob_num_conditions(solver->prob), solver->prob->conditions, 120, UINT32_MAX, 0, 0);
#endif
ef_solver_start(solver);
while (solver->status == EF_STATUS_SEARCHING && i < max) {
tprintf(solver->trace, 3, "(EF Iteration %"PRIu32", scan_idx = %"PRIu32")\n", i, solver->scan_idx);
stat = ef_solver_check_exists(solver);
switch (stat) {
case STATUS_SAT:
case STATUS_UNKNOWN:
// we have a candidate exists model
// check it and learn what we can
#if EF_VERBOSE
// FOR DEBUGGING
printf("Candidate exists model:\n");
print_ef_solution(stdout, solver);
printf("\n");
#endif
tputs(solver->trace, 4, "(EF: Found candidate model)\n");
ef_solver_check_exists_model(solver);
break;
case STATUS_UNSAT:
tputs(solver->trace, 4, "(EF: No candidate model)\n");
solver->status = EF_STATUS_UNSAT;
break;
case STATUS_INTERRUPTED:
tputs(solver->trace, 4, "(EF: Interrupted)\n");
solver->status = EF_STATUS_INTERRUPTED;
break;
default:
solver->status = EF_STATUS_CHECK_ERROR;
solver->error_code = stat;
break;
}
i ++;
}
/*
* Cleanup and set status if i == max
*/
if (solver->status != EF_STATUS_SAT && solver->exists_model != NULL) {
yices_free_model(solver->exists_model);
solver->exists_model = NULL;
if (solver->status == EF_STATUS_SEARCHING) {
assert(i == max);
solver->status = EF_STATUS_UNKNOWN;
}
}
solver->iters = i;
tputs(solver->trace, 3, "(EF: done)\n\n");
}