void clause_list_concat(samp_clause_list_t *list_src, samp_clause_list_t *list_dst) {
assert(valid_clause_list(list_src));
assert(valid_clause_list(list_dst));
list_dst->tail->link = list_src->head->link;
if (!is_empty_clause_list(list_src)) {
list_dst->tail = list_src->tail;
}
list_dst->length += list_src->length;
list_src->head->link = NULL;
list_src->tail = list_src->head;
list_src->length = 0;
assert(valid_clause_list(list_src));
assert(valid_clause_list(list_dst));
}
static bool valid_watched_lit(rule_inst_table_t *rule_inst_table, samp_literal_t lit,
atom_table_t *atom_table) {
valid_clause_list(&rule_inst_table->watched[lit]);
bool lit_true = (is_pos(lit) && assigned_true(atom_table->assignment[var_of(lit)]))
|| (is_neg(lit) && assigned_false(atom_table->assignment[var_of(lit)]));
assert(is_empty_clause_list(&rule_inst_table->watched[lit]) || lit_true);
if (!is_empty_clause_list(&rule_inst_table->watched[lit]) && !lit_true) {
return false;
}
samp_clause_t *ptr;
samp_clause_t *cls;
for (ptr = rule_inst_table->watched[lit].head;
ptr != rule_inst_table->watched[lit].tail;
ptr = next_clause_ptr(ptr)) {
cls = ptr->link;
assert(clause_contains_lit(cls, lit));
if (!clause_contains_lit(cls, lit))
return false;
}
return true;
}
/*
* Propagates a truth assignment on a link of watched clauses for a literal
* that has been assigned false. All the literals are assumed to have truth
* values. The watched literal points to a true literal if there is one in
* the clause. Whenever a watched literal is assigned false, the
* propagation must find a new true literal, or retain the existing one. If
* a clause is falsified, its weight is added to the delta cost. The
* clauses containing the negation of the literal must be reevaluated and
* assigned true if previously false.
*/
static void link_propagate(samp_table_t *table, samp_literal_t lit) {
rule_inst_table_t *rule_inst_table = &table->rule_inst_table;
#ifndef NDEBUG
atom_table_t *atom_table = &table->atom_table;
#endif
/* the assignment of the lit has just changed to false */
assert(assigned_false_lit(atom_table->assignment, lit));
/* since the assignment of the lit was true, the negate of the lit
* should have an empty watched list */
assert(is_empty_clause_list(&rule_inst_table->watched[not(lit)]));
/* watched list of lit needs to be rescaned */
clause_list_concat(&rule_inst_table->watched[lit], &rule_inst_table->live_clauses);
/* unsat clause list is dirty, need to rescan */
clause_list_concat(&rule_inst_table->unsat_clauses, &rule_inst_table->live_clauses);
}
