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#include "theory/idl/theory_idl.h"
#include "theory/idl/options.h"
#include "theory/rewriter.h"
#include <set>
#include <queue>
using namespace std;
using namespace CVC4;
using namespace theory;
using namespace idl;
TheoryIdl::TheoryIdl(context::Context* c, context::UserContext* u, OutputChannel& out,
Valuation valuation, const LogicInfo& logicInfo, QuantifiersEngine* qe)
: Theory(THEORY_ARITH, c, u, out, valuation, logicInfo, qe)
, d_model(c)
, d_assertionsDB(c)
{}
Node TheoryIdl::ppRewrite(TNode atom) {
if (atom.getKind() == kind::EQUAL && options::idlRewriteEq()) {
// If the option is turned on, each equality into two inequalities. This in
// effect removes equalities, and theorefore dis-equalities too.
Node leq = NodeBuilder<2>(kind::LEQ) << atom[0] << atom[1];
Node geq = NodeBuilder<2>(kind::GEQ) << atom[0] << atom[1];
Node rewritten = Rewriter::rewrite(leq.andNode(geq));
return rewritten;
} else {
return atom;
}
}
void TheoryIdl::check(Effort level) {
while(!done()) {
// Get the next assertion
Assertion assertion = get();
Debug("theory::idl") << "TheoryIdl::check(): processing " << assertion.assertion << std::endl;
// Convert the assertion into the internal representation
IDLAssertion idlAssertion(assertion.assertion);
Debug("theory::idl") << "TheoryIdl::check(): got " << idlAssertion << std::endl;
if (idlAssertion.ok()) {
if (idlAssertion.getOp() == kind::DISTINCT) {
// We don't handle dis-equalities
d_out->setIncomplete();
} else {
// Process the convex assertions immediately
bool ok = processAssertion(idlAssertion);
if (!ok) {
// In conflict, we're done
return;
}
}
} else {
// Not an IDL assertion, set incomplete
d_out->setIncomplete();
}
}
}
bool TheoryIdl::processAssertion(const IDLAssertion& assertion) {
Debug("theory::idl") << "TheoryIdl::processAssertion(" << assertion << ")" << std::endl;
// Add the constraint (x - y op c) to the list assertions of x
d_assertionsDB.add(assertion, assertion.getX());
// Update the model, if forced by the assertion
bool y_updated = assertion.propagate(d_model);
// If the value of y was updated, we might need to update further
if (y_updated) {
std::queue<TNode> queue; // Queue of variables to consider
std::set<TNode> inQueue; // Current elements of the queue
// Add the first updated variable to the queue
queue.push(assertion.getY());
inQueue.insert(assertion.getY());
while (!queue.empty()) {
// Pop a new variable x off the queue
TNode x = queue.front();
queue.pop();
inQueue.erase(x);
// Go through the constraint (x - y op c), and update values of y
IDLAssertionDB::iterator it(d_assertionsDB, x);
while (!it.done()) {
// Get the assertion and update y
IDLAssertion x_y_assertion = it.get();
y_updated = x_y_assertion.propagate(d_model);
// If updated add to the queue
if (y_updated) {
// If the variable that we updated is the same as the first
// variable that we updated, it's a cycle of updates => conflict
if (x_y_assertion.getY() == assertion.getX()) {
std::vector<TNode> reasons;
d_model.getReasonCycle(x_y_assertion.getY(), reasons);
// Construct the reason of the conflict
Node conflict = NodeManager::currentNM()->mkNode(kind::AND, reasons);
d_out->conflict(conflict);
return false;
} else {
// No cycle, just a model update, so we add to the queue
TNode y = x_y_assertion.getY();
if (inQueue.count(y) == 0) {
queue.push(y);
inQueue.insert(x_y_assertion.getY());
}
}
}
// Go to the next constraint
it.next();
}
}
}
// Everything fine, no conflict
return true;
}
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