// computes the reason why a set of atoms is unfounded
void DefaultUnfoundedCheck::computeReason() {
assert(reasonExt_.empty());
uint32 ufsScc = graph_->getAtomNode(unfounded_.front()).scc;
for (VarVec::size_type i = unfounded_.front_; i != unfounded_.vec_.size(); ++i) {
const DependencyGraph::AtomNode& atom = graph_->getAtomNode(unfounded_.vec_[i]);
if (!solver_->isFalse(atom.lit)) {
assert(atom.scc == ufsScc);
for (const NodeId* x = atom.bodies(); x != atom.bodies_end(); ++x) {
addIfReason(graph_->getBody(*x), ufsScc);
}
}
}
for (VarVec::size_type i = 0; i != reasonExt_.size(); ++i) {
bodies_[reasonExt_[i]].picked = 0;
}
reasonExt_.clear();
info_ = ClauseInfo(Constraint_t::learnt_loop);
uint32 dl = solver_->finalizeConflictClause(activeClause_, info_);
assert(dl == solver_->decisionLevel() && "Loop nogood must contain a literal from current DL!");
double ratio = activeClause_.size()/double(solver_->decisionLevel()+1);
if (ratio > 10 && activeClause_.size() > 100 && !solver_->isFalse(activeClause_[0])) {
activeClause_.resize(1);
// replace reason with current decision sequence
// start with last decision so that watches are correctly initialized
for (uint32 x = dl; x; --x) {
activeClause_.push_back(~solver_->decision(x));
}
}
}
ClauseHead* set(Solver& s, LitVec& c) {
ClauseCreator::Result ret;
uint32 flags = ClauseCreator::clause_explicit|ClauseCreator::clause_no_add;
if (shared_) {
ret = ClauseCreator::integrate(s, createShared(c), flags);
}
else {
ret = ClauseCreator::create(s, c, flags, ClauseInfo(Constraint_t::learnt_other));
}
return ret.local;
}
bool ClauseHead::toImplication(Solver& s) {
ConstraintType t = ClauseHead::type();
uint32 sz = isSentinel(head_[1]) ? 1 : 2 + (!s.isFalse(head_[2]) || s.level(head_[2].var()) > 0);
ClauseRep rep = ClauseRep::create(head_, sz, ClauseInfo(t).setLbd(2).setTagged(tagged()));
bool implicit = s.allowImplicit(rep);
bool locked = ClauseHead::locked(s) && s.decisionLevel() > 0;
rep.prep = 1;
if ((locked || !implicit) && sz > 1) { return false; }
s.add(rep, false);
detach(s);
return true;
}
