//undoes the last literal decision and the corresponding implications obtained by unit resolution
//
//if the current decision level is L in the beginning of the call, it should be updated
//to L-1 before the call ends
void sat_undo_decide_literal(SatState* sat_state) {
Lit* lit = vector_top(&sat_state->ds);
sat_restore_literal(sat_state, lit);
vector_pop(&sat_state->ds);
vector_pop(&sat_state->s);
sat_undo_unit_resolution(sat_state);
}
//undoes the last literal decision and the corresponding implications obtained by unit resolution
//
//if the current decision level is L in the beginning of the call, it should be updated
//to L-1 before the call ends
void sat_undo_decide_literal(SatState* sat_state) {
c2dSize sz = sat_state->num_decided_literals;
while (sz > 0 && sat_state->decided_literals[sz - 1]->decision_level == sat_state->cur_level) {
undo_instantiate_literal(sat_state->decided_literals[sz - 1]);
--sz;
}
sat_state->num_decided_literals = sz;
sat_undo_unit_resolution(sat_state);
--sat_state->cur_level;
}
NnfManager* compile_vtree(VtreeManager* manager, SatState* sat_state) {
NNF_NODE node;
Clause* learned_clause = NULL;
DVtree* vtree = manager->vtree;
NnfManager* nnf_manager = nnf_manager_new(sat_state,UNIQUE_TABLE_CAPACITY);
if(sat_unit_resolution(sat_state)) { //unit resolution succeeded
compile_dispatcher(&node,&learned_clause,vtree,manager,nnf_manager,sat_state);
if(learned_clause!=NULL) node = ZERO_NNF_NODE; //cnf is inconsistent
}
else node = ZERO_NNF_NODE; //cnf is inconsistent
sat_undo_unit_resolution(sat_state);
nnf_manager_set_root(node,nnf_manager);
return nnf_manager;
}
