void Solver::aspCallsOnNewRowFromChild(ItemTree::Children::const_iterator newRow, const DecompositionPtr& originatingChild, Clasp::ClaspFacade& clasp)
{
std::vector<std::pair<Decomposition*, ItemTree::Children::const_iterator>> rowIterators; // Key: Child node; Value: Row in the item tree at this child
rowIterators.reserve(decomposition.getChildren().size());
// At index 0 we will store newRow. This iterator will not be incremented.
rowIterators.emplace_back(originatingChild.get(), newRow);
for(const auto& child : decomposition.getChildren()) {
if(child != originatingChild) {
rowIterators.emplace_back(child.get(), dynamic_cast<Solver&>(child->getSolver()).getItemTreeSoFar()->getChildren().begin());
assert(rowIterators.back().second != dynamic_cast<Solver&>(child->getSolver()).getItemTreeSoFar()->getChildren().end());
}
}
do {
ItemTreeNode::ExtensionPointerTuple extendedRows;
for(const auto& nodeAndRow : rowIterators)
extendedRows.emplace(nodeAndRow.first->getNode().getGlobalId(), (*nodeAndRow.second)->getNode());
claspCallback->setExtendedRows(std::move(extendedRows));
{
Clasp::Asp::LogicProgram& prg = static_cast<Clasp::Asp::LogicProgram&>(clasp.update());
for(const auto& nodeAndRow : rowIterators) {
for(const auto& item : (*nodeAndRow.second)->getNode()->getItems()) {
// std::cout << "W " << std::this_thread::get_id() << " [" << decomposition.getNode().getGlobalId() << "]: Setting " << item << " to true\n";
prg.freeze(itemsToVars.at(item), Clasp::value_true);
}
}
}
clasp.prepare();
claspCallback->prepare(clasp.ctx.symbolTable());
clasp.solve(claspCallback.get());
{
// XXX Necessary to update so often? Is the overhead bad?
Clasp::Asp::LogicProgram& prg = static_cast<Clasp::Asp::LogicProgram&>(clasp.update());
for(const auto& nodeAndRow : rowIterators) {
for(const auto& item : (*nodeAndRow.second)->getNode()->getItems()) {
// std::cout << "W " << std::this_thread::get_id() << " [" << decomposition.getNode().getGlobalId() << "]: Setting " << item << " to false\n";
prg.freeze(itemsToVars.at(item), Clasp::value_false);
}
}
}
} while(nextRowCombination(rowIterators));
}
void Solver::workerThreadMain()
{
std::unique_lock<std::mutex> lock(workerMutex);
// Set up ASP solver
Clasp::ClaspFacade clasp;
Clasp::ClaspConfig config;
config.solve.numModels = 0;
Clasp::Asp::LogicProgram& claspProgramBuilder = dynamic_cast<Clasp::Asp::LogicProgram&>(clasp.startAsp(config, true));
std::unique_ptr<Gringo::Output::LparseOutputter> lpOut(new GringoOutputProcessor(claspProgramBuilder));
claspCallback.reset(new ClaspCallback(dynamic_cast<GringoOutputProcessor&>(*lpOut), app, *this, lock));
std::unique_ptr<Gringo::Output::OutputBase> out(new Gringo::Output::OutputBase({}, *lpOut));
Gringo::Input::Program program;
Gringo::Scripts scripts;
Gringo::Defines defs;
Gringo::Input::NongroundProgramBuilder gringoProgramBuilder(scripts, program, *out, defs);
Gringo::Input::NonGroundParser parser(gringoProgramBuilder);
// Input: Original problem instance
std::unique_ptr<std::stringstream> instanceInput(new std::stringstream);
*instanceInput << app.getInputString();
// Input: Decomposition
std::unique_ptr<std::stringstream> decompositionInput(new std::stringstream);
solver::asp::Solver::declareDecomposition(decomposition, *decompositionInput);
app.getPrinter().solverInvocationInput(decomposition, decompositionInput->str());
// Pass input to ASP solver
for(const auto& file : encodingFiles)
parser.pushFile(std::string(file));
parser.pushStream("<instance>", std::move(instanceInput));
parser.pushStream("<decomposition>", std::move(decompositionInput));
parser.parse();
// Ground
program.rewrite(defs);
program.check();
if(Gringo::message_printer()->hasError())
throw std::runtime_error("Grounding stopped because of errors");
auto gPrg = program.toGround(out->domains);
Gringo::Ground::Parameters params;
params.add("base", {});
gPrg.ground(params, scripts, *out);
params.clear();
// Prepare for solving. (This makes clasp's symbol table available.)
clasp.prepare();
claspCallback->prepare(clasp.ctx.symbolTable());
// We need to know which clasp variable corresponds to each childItem(_) atom.
for(const auto& pair : clasp.ctx.symbolTable()) {
if(!pair.second.name.empty()) {
const std::string name = pair.second.name.c_str();
if(name.compare(0, 10, "childItem(") == 0) {
const std::string argument = name.substr(10, name.length()-11);
itemsToVars.emplace(argument, pair.first);
}
}
}
// Let main thread finish the constructor
wakeMainThreadRequested = true;
wakeMainThread.notify_one();
// Wait until we should do work
wakeWorkerThread.wait(lock, [&]() { return wakeWorkerThreadRequested; });
wakeWorkerThreadRequested = false;
if(decomposition.getChildren().empty()) {
// This is a leaf solver.
clasp.solve(claspCallback.get());
}
else {
// Get the first row from each child node
std::unordered_map<unsigned int, ItemTree::Children::const_iterator> childRows;
childRows.reserve(decomposition.getChildren().size());
for(const auto& child : decomposition.getChildren()) {
const ItemTree::Children::const_iterator newRow = dynamic_cast<Solver&>(child->getSolver()).nextRow();
if(newRow == dynamic_cast<Solver&>(child->getSolver()).getItemTreeSoFar()->getChildren().end()) {
// Notify main thread that solving is complete
noMoreModels = true;
wakeMainThreadRequested = true;
wakeMainThread.notify_one();
return;
}
childRows.emplace(child->getNode().getGlobalId(), newRow);
}
// Let the combination of these rows be the input for our ASP call
ItemTreeNode::ExtensionPointerTuple rootExtensionPointers;
for(const auto& child : decomposition.getChildren())
rootExtensionPointers.emplace(child->getNode().getGlobalId(), dynamic_cast<Solver&>(child->getSolver()).getItemTreeSoFar()->getNode());
claspCallback->setRootExtensionPointers(std::move(rootExtensionPointers));
ItemTreeNode::ExtensionPointerTuple extendedRows;
for(const auto& nodeIdAndRow : childRows)
extendedRows.emplace(nodeIdAndRow.first, (*nodeIdAndRow.second)->getNode());
claspCallback->setExtendedRows(std::move(extendedRows));
{
Clasp::Asp::LogicProgram& prg = static_cast<Clasp::Asp::LogicProgram&>(clasp.update());
for(const auto& nodeIdAndRow : childRows) {
for(const auto& item : (*nodeIdAndRow.second)->getNode()->getItems()) {
prg.freeze(itemsToVars.at(item), Clasp::value_true);
}
}
}
clasp.prepare();
claspCallback->prepare(clasp.ctx.symbolTable());
clasp.solve(claspCallback.get());
{
// XXX Necessary to update so often? Is the overhead bad?
Clasp::Asp::LogicProgram& prg = static_cast<Clasp::Asp::LogicProgram&>(clasp.update());
for(const auto& nodeIdAndRow : childRows) {
for(const auto& item : (*nodeIdAndRow.second)->getNode()->getItems()) {
prg.freeze(itemsToVars.at(item), Clasp::value_false);
}
}
}
// Now there are no models anymore for this row combination
// Until there are no new rows anymore, generate one new row at some child node and combine it with all rows from other child nodes
bool foundNewRow;
do {
foundNewRow = false;
for(const auto& child : decomposition.getChildren()) {
ItemTree::Children::const_iterator newRow = dynamic_cast<Solver&>(child->getSolver()).nextRow();
if(newRow != dynamic_cast<Solver&>(child->getSolver()).getItemTreeSoFar()->getChildren().end()) {
foundNewRow = true;
aspCallsOnNewRowFromChild(newRow, child, clasp);
}
}
} while(foundNewRow);
}
// Notify main thread that solving is complete
noMoreModels = true;
wakeMainThreadRequested = true;
wakeMainThread.notify_one();
}