bool SolveAlgorithm::solve(SharedContext& ctx, const SolveParams& p, const LitVec& assume) {
assumptions_ = assume;
if (!isSentinel(ctx.tagLiteral())) { assumptions_.push_back(ctx.tagLiteral()); }
bool more = limits_.conflicts == 0 || doSolve(*ctx.master(), p);
ctx.enumerator()->reportResult(!more);
if (!isSentinel(ctx.tagLiteral())) { assumptions_.pop_back(); }
ctx.detach(*ctx.master());
return more;
}
uint32 SharedDependencyGraph::addBody(SharedContext& ctx, PrgBodyNode* b, const AtomList& prgAtoms) {
if (b->visited()) { // first time we see this body -
b->setVisited(false); // mark as visited and create node
b->setUfsNode( (NodeId)bodies_.size(), false );
bodies_.push_back(BodyNode(b));
BodyNode* bn = &bodies_.back();
// Init node
VarVec preds, succs;
if (bn->scc != PrgNode::noScc) {
const bool weights = b->type() == PrgBodyNode::SUM_BODY;
for (uint32 p = 0; p != b->posSize(); ++p) {
PrgAtomNode* pred = prgAtoms[b->pos(p)];
if (relevantPrgAtom(*ctx.master(), pred) && pred->scc() == bn->scc) {
preds.push_back( pred->ufsNode() );
if (weights) {
preds.push_back( b->weight(p, true) );
}
}
}
preds.push_back(idMax);
if (bn->extended()) {
for (uint32 n = 0; n != b->size(); ++n) {
PrgAtomNode* pred = prgAtoms[b->goal(n).var()];
Literal lit = b->goal(n).sign() ? ~pred->literal() : pred->literal();
if ( (b->goal(n).sign() || pred->scc() != bn->scc) && !ctx.master()->isFalse(lit) ) {
preds.push_back(lit.asUint());
if (weights) {
preds.push_back(b->weight(n));
}
}
}
preds.push_back(idMax);
}
}
for (HeadVec::const_iterator it = b->heads_begin(), end = b->heads_end(); it != end; ++it) {
PrgAtomNode* a = prgAtoms[it->node()];
if (relevantPrgAtom(*ctx.master(), a)) {
NodeId id = a->ufsNode();
VarVec::iterator insPos = bn->scc == a->scc() ? succs.begin() : succs.end();
succs.insert(insPos, id);
}
}
bn->adj_ = new NodeId[succs.size() + bn->extended() + preds.size()];
if (bn->extended()) {
*bn->adj_= b->bound();
}
bn->sep_ = std::copy(succs.begin(), succs.end(), bn->adj_ + bn->extended());
std::copy(preds.begin(), preds.end(), bn->sep_);
ctx.setFrozen(b->var(), true);
}
return b->ufsNode();
}
void testMiniProject() {
SharedContext ctx;
Solver& solver = *ctx.master();
builder.startProgram(ctx, ProgramBuilder::EqOptions().noEq().noScc())
.setAtomName(1, "a").setAtomName(2, "b").setAtomName(3, "_x")
.startRule(CHOICERULE).addHead(1).addHead(2).addHead(3).endRule()
.startRule().addHead(3).addToBody(1, false).endRule()
.startRule().addHead(3).addToBody(2, false).endRule()
.startRule(OPTIMIZERULE).addToBody(3, true).endRule()
;
CPPUNIT_ASSERT_EQUAL(true, builder.endProgram());
std::auto_ptr<BacktrackEnumerator> e(new BacktrackEnumerator(0));
e->setEnableProjection(true);
e->enumerate(0);
MinimizeBuilder b;
builder.addMinimize(b);
ctx.addEnumerator(e.release());
ctx.enumerator()->setMinimize(b.build(ctx));
ctx.endInit();
SymbolTable& index = ctx.symTab();
solver.assume(index[1].lit);
solver.propagate();
solver.assume(index[2].lit);
solver.propagate();
solver.assume(index[3].lit);
solver.propagate();
CPPUNIT_ASSERT(solver.numVars() == solver.numAssignedVars());
CPPUNIT_ASSERT_EQUAL(Enumerator::enumerate_continue, ctx.enumerator()->backtrackFromModel(solver));
CPPUNIT_ASSERT(false == solver.propagate());
solver.backtrack();
CPPUNIT_ASSERT(false == solver.propagate() && !solver.resolveConflict());
ctx.detach(solver);
}
void ModelEnumerator::addProjectVar(SharedContext& ctx, Var v, bool tag) {
if (ctx.master()->value(v) == value_free && (!tag || !ctx.marked(posLit(v)))) {
project_->push_back(v);
ctx.setFrozen(v, true);
ctx.setProject(v, true);
if (tag) { ctx.mark(posLit(v)); ctx.mark(negLit(v)); }
}
}
void testProjectBug() {
SharedContext ctx;
Solver& solver = *ctx.master();
builder.startProgram(ctx, ProgramBuilder::EqOptions().noEq().noScc())
.setAtomName(1, "x").setAtomName(2, "y").setAtomName(3, "z").setAtomName(4, "_p").setAtomName(5, "_q").setAtomName(6, "_r")
.startRule(CHOICERULE).addHead(1).addHead(2).addHead(4).endRule() // {x,y,_p}
.startRule().addHead(5).addToBody(1, true).addToBody(4, true).endRule() // _q :- x,_p.
.startRule().addHead(6).addToBody(2, true).addToBody(4, true).endRule() // _r :- y,_p.
.startRule().addHead(3).addToBody(5, true).addToBody(6, true).endRule() // z :- _q,_r.
;
CPPUNIT_ASSERT_EQUAL(true, builder.endProgram());
std::auto_ptr<BacktrackEnumerator> e(new BacktrackEnumerator(7,0));
e->setEnableProjection(true);
e->enumerate(0);
ctx.addEnumerator(e.release());
ctx.endInit();
SymbolTable& index = ctx.symTab();
solver.assume(index[1].lit);
solver.propagate();
solver.assume(index[2].lit);
solver.propagate();
solver.assume(index[4].lit);
solver.propagate();
CPPUNIT_ASSERT(solver.numVars() == solver.numAssignedVars());
CPPUNIT_ASSERT_EQUAL(Enumerator::enumerate_continue, ctx.enumerator()->backtrackFromModel(solver));
solver.undoUntil(0);
uint32 numT = 0;
if (solver.value(index[1].lit.var()) == value_free) {
solver.assume(index[1].lit) && solver.propagate();
++numT;
}
else if (solver.isTrue(index[1].lit)) {
++numT;
}
if (solver.value(index[2].lit.var()) == value_free) {
solver.assume(index[2].lit) && solver.propagate();
++numT;
}
else if (solver.isTrue(index[2].lit)) {
++numT;
}
if (solver.value(index[4].lit.var()) == value_free) {
solver.assume(index[4].lit) && solver.propagate();
}
if (solver.isTrue(index[3].lit)) {
++numT;
}
CPPUNIT_ASSERT(numT < 3);
ctx.detach(solver);
}
void testParallelRecord() {
SharedContext ctx; Solver& solver = *ctx.master();
builder.startProgram(ctx, ProgramBuilder::EqOptions().noEq().noScc())
.setAtomName(1, "a").setAtomName(2, "b").setAtomName(3, "c").setAtomName(4, "d")
.startRule(CHOICERULE).addHead(1).addHead(2).addHead(3).addHead(4).endRule()
;
CPPUNIT_ASSERT_EQUAL(true, builder.endProgram());
ctx.setSolvers(2);
ctx.addEnumerator(new RecordEnumerator(0));
ctx.enumerator()->enumerate(0);
ctx.endInit();
Solver solver2;
ctx.attach(solver2);
SymbolTable& index = ctx.symTab();
solver.assume(index[1].lit) && solver.propagate();
solver.assume(index[2].lit) && solver.propagate();
solver.assume(index[3].lit) && solver.propagate();
solver.assume(index[4].lit) && solver.propagate();
CPPUNIT_ASSERT_EQUAL(uint32(0), solver.numFreeVars());
ctx.enumerator()->backtrackFromModel(solver);
solver.undoUntil(0);
CPPUNIT_ASSERT_EQUAL(true, ctx.enumerator()->update(solver2, false));
solver2.assume(index[1].lit) && solver2.propagate();
solver2.assume(index[2].lit) && solver2.propagate();
solver2.assume(index[3].lit) && solver2.propagate();
CPPUNIT_ASSERT(solver2.isFalse(index[4].lit) && solver2.propagate());
CPPUNIT_ASSERT_EQUAL(uint32(0), solver2.numFreeVars());
ctx.enumerator()->backtrackFromModel(solver2);
solver.undoUntil(0);
CPPUNIT_ASSERT_EQUAL(true, ctx.enumerator()->update(solver, false));
solver.assume(index[1].lit) && solver.propagate();
solver.assume(index[2].lit) && solver.propagate();
CPPUNIT_ASSERT(solver.isFalse(index[3].lit));
ctx.detach(solver2);
ctx.detach(solver);
solver2.undoUntil(0);
ctx.attach(solver2);
solver2.assume(index[1].lit) && solver2.propagate();
solver2.assume(index[2].lit) && solver2.propagate();
solver2.assume(index[3].lit) && solver2.propagate();
CPPUNIT_ASSERT(solver2.value(index[4].lit.var()) == value_free);
}
void testParallelUpdate() {
SharedContext ctx; Solver& solver = *ctx.master();
builder.startProgram(ctx, ProgramBuilder::EqOptions().noEq().noScc())
.setAtomName(1, "a").setAtomName(2, "b").setAtomName(3, "c")
.startRule(CHOICERULE).addHead(1).addHead(2).addHead(3).endRule()
.startRule(OPTIMIZERULE).addToBody(2, true).endRule()
;
CPPUNIT_ASSERT_EQUAL(true, builder.endProgram());
MinimizeBuilder minBuilder;
builder.addMinimize(minBuilder);
ctx.setSolvers(2);
ctx.addEnumerator(new RecordEnumerator(0));
ctx.enumerator()->enumerate(0);
ctx.enumerator()->setMinimize(minBuilder.build(ctx));
ctx.endInit();
Solver solver2;
ctx.attach(solver2);
SymbolTable& index = ctx.symTab();
// a
solver.assume(index[1].lit);
solver.pushRootLevel(1);
solver.propagate();
// ~a
solver2.assume(~index[1].lit);
solver2.pushRootLevel(1);
solver2.propagate();
// M1: ~b, c
solver.assume(~index[2].lit);
solver.propagate();
solver.assume(index[3].lit);
solver.propagate();
CPPUNIT_ASSERT_EQUAL(uint32(0), solver.numFreeVars());
ctx.enumerator()->backtrackFromModel(solver);
solver.undoUntil(0);
// M2: ~b, ~c
solver2.assume(~index[2].lit);
solver2.propagate();
solver2.assume(~index[3].lit);
solver2.propagate();
// M2 is NOT VALID!
CPPUNIT_ASSERT_EQUAL(false, ctx.enumerator()->update(solver2, true));
}
void testTerminateRemovesWatches() {
SharedContext ctx; Solver& solver = *ctx.master();
builder.startProgram(ctx, ProgramBuilder::EqOptions().noEq().noScc())
.setAtomName(1, "a").setAtomName(2, "b").setAtomName(3, "c").setAtomName(4, "d")
.startRule(CHOICERULE).addHead(1).addHead(2).addHead(3).addHead(4).endRule()
;
CPPUNIT_ASSERT_EQUAL(true, builder.endProgram());
ctx.addEnumerator(new RecordEnumerator(0));
ctx.enumerator()->enumerate(0);
CPPUNIT_ASSERT_EQUAL(true, ctx.endInit());
SymbolTable& index = ctx.symTab();
solver.assume(index[1].lit) && solver.propagate();
solver.assume(index[2].lit) && solver.propagate();
solver.assume(index[3].lit) && solver.propagate();
solver.assume(index[4].lit) && solver.propagate();
CPPUNIT_ASSERT_EQUAL(uint32(0), solver.numFreeVars());
ctx.enumerator()->backtrackFromModel(solver);
uint32 numW = solver.numWatches(index[1].lit) + solver.numWatches(index[2].lit) + solver.numWatches(index[3].lit) + solver.numWatches(index[4].lit);
CPPUNIT_ASSERT(numW > 0);
ctx.detach(solver);
numW = solver.numWatches(index[1].lit) + solver.numWatches(index[2].lit) + solver.numWatches(index[3].lit) + solver.numWatches(index[4].lit);
CPPUNIT_ASSERT(numW == 0);
}
// Creates a positive-body-atom-dependency graph (PBADG)
// The PBADG contains a node for each atom A of a non-trivial SCC and
// a node for each body B, s.th. there is a non-trivially connected atom A with
// B in body(A).
// Pre : a->ignore = 0 for all new and relevant atoms a
// Pre : b->visited = 1 for all new and relevant bodies b
// Post: a->ignore = 1 for all atoms that were added to the PBADG
// Post: b->visited = 0 for all bodies that were added to the PBADG
void SharedDependencyGraph::addSccs(SharedContext& ctx, const AtomList& sccAtoms, const AtomList& prgAtoms, const BodyList& prgBodies) {
// Pass 1: Create graph atom nodes and estimate number of bodies
NodeId atomId = static_cast<NodeId>(atoms_.size());
atoms_.reserve(atoms_.size() + sccAtoms.size());
AtomList::size_type numBodies = 0;
for (AtomList::size_type i = 0, end = sccAtoms.size(); i != end; ++i) {
PrgAtomNode* a = sccAtoms[i];
if (relevantPrgAtom(*ctx.master(), a)) {
// initialize graph atom node
atoms_.push_back(AtomNode());
AtomNode& ua = atoms_.back();
ua.lit = a->literal();
ua.scc = a->scc();
numBodies += a->preds.size();
// store link between program node and graph node for later lookup
a->setUfsNode(atomId, true);
// atom is defined by more than just a bunch of clauses
ctx.setFrozen(a->var(), true);
++atomId;
}
}
// Pass 2: Init atom nodes and create body nodes
VarVec preds, succs, succsExt;
NodeId* temp;
bodies_.reserve(bodies_.size() + numBodies/2);
for (AtomList::size_type i = 0, end = sccAtoms.size(); i != end; ++i) {
PrgAtomNode* a = sccAtoms[i];
if (relevantPrgAtom(*ctx.master(), a)) {
AtomNode& ua = atoms_[a->ufsNode()];
for (HeadVec::const_iterator it = a->preds.begin(), endIt = a->preds.end(); it != endIt; ++it) {
PrgBodyNode* prgBody = prgBodies[it->node()];
if (relevantPrgBody(*ctx.master(), prgBody)) {
NodeId bId = addBody(ctx, prgBody, prgAtoms);
VarVec::iterator insPos = prgBody->scc() == a->scc() ? preds.end() : preds.begin();
preds.insert(insPos, bId);
if (it->choice()) {
ua.type |= Node::type_in_choice;
}
}
}
for (VarVec::const_iterator it = a->posDep.begin(), endIt = a->posDep.end(); it != endIt; ++it) {
PrgBodyNode* prgBody = prgBodies[*it];
if (prgBody->scc() == a->scc() && relevantPrgBody(*ctx.master(), prgBody)) {
NodeId bodyId = addBody(ctx, prgBody, prgAtoms);
if (!bodies_[bodyId].extended()) {
succs.push_back(bodyId);
}
else {
succsExt.push_back(bodyId);
succsExt.push_back(bodies_[bodyId].get_pred_idx(a->ufsNode()));
assert(bodies_[bodyId].get_pred(succsExt.back()) == a->ufsNode());
ua.type |= Node::type_ext;
}
}
}
succs.push_back(idMax);
if (!succsExt.empty()) {
succsExt.push_back(idMax);
}
ua.adj_ = new NodeId[preds.size()+succs.size()+succsExt.size()];
ua.sep_ = std::copy(preds.begin(), preds.end(), ua.adj_);
temp = std::copy(succs.begin(), succs.end(), ua.sep_);
std::copy(succsExt.begin(), succsExt.end(), temp);
preds.clear(); succs.clear(); succsExt.clear();
}
}
}