unsigned QuickXPlain::selectUnsatCore(unsigned low, unsigned high,
std::vector<TNode>& conflict) {
Assert(!d_solver->getConflict().isNull() &&
d_solver->inConflict());
Node query_confl = d_solver->getConflict();
// conflict wasn't actually minimized
if (query_confl.getNumChildren() == high - low + 1) {
return high;
}
TNodeSet nodes;
for (unsigned i = low; i <= high; i++) {
nodes.insert(conflict[i]);
}
unsigned write = low;
for (unsigned i = 0; i < query_confl.getNumChildren(); ++i) {
TNode current = query_confl[i];
// the conflict can have nodes in lower decision levels
if (nodes.find(current) != nodes.end()) {
conflict[write++] = current;
nodes.erase(nodes.find(current));
}
}
// if all of the nodes in the conflict were on a lower level
if (write == low) {
return low;
}
Assert (write != 0);
unsigned new_high = write - 1;
for (TNodeSet::const_iterator it = nodes.begin(); it != nodes.end(); ++it) {
conflict[write++] = *it;
}
Assert (write -1 == high);
Assert (new_high <= high);
return new_high;
}
