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/********************* */
/*! \file candidate_generator.cpp
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds, Morgan Deters, Francois Bobot
** This file is part of the CVC4 project.
** Copyright (c) 2009-2019 by the authors listed in the file AUTHORS
** in the top-level source directory) and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief Implementation of theory uf candidate generator class
**/
#include "theory/quantifiers/ematching/candidate_generator.h"
#include "options/quantifiers_options.h"
#include "theory/quantifiers/inst_match.h"
#include "theory/quantifiers/instantiate.h"
#include "theory/quantifiers/term_database.h"
#include "theory/quantifiers/term_util.h"
#include "theory/quantifiers_engine.h"
#include "theory/theory_engine.h"
#include "theory/uf/theory_uf.h"
using namespace std;
using namespace CVC4;
using namespace CVC4::kind;
using namespace CVC4::context;
using namespace CVC4::theory;
using namespace CVC4::theory::inst;
bool CandidateGenerator::isLegalCandidate( Node n ){
return d_qe->getTermDatabase()->isTermActive( n ) && ( !options::cbqi() || !quantifiers::TermUtil::hasInstConstAttr(n) );
}
CandidateGeneratorQE::CandidateGeneratorQE(QuantifiersEngine* qe, Node pat)
: CandidateGenerator(qe),
d_term_iter(-1),
d_term_iter_limit(0),
d_mode(cand_term_none)
{
d_op = qe->getTermDatabase()->getMatchOperator( pat );
Assert( !d_op.isNull() );
}
void CandidateGeneratorQE::resetInstantiationRound(){
d_term_iter_limit = d_qe->getTermDatabase()->getNumGroundTerms( d_op );
}
void CandidateGeneratorQE::reset( Node eqc ){
d_term_iter = 0;
if( eqc.isNull() ){
d_mode = cand_term_db;
}else{
if( isExcludedEqc( eqc ) ){
d_mode = cand_term_none;
}else{
eq::EqualityEngine* ee = d_qe->getEqualityQuery()->getEngine();
if( ee->hasTerm( eqc ) ){
TNodeTrie* tat = d_qe->getTermDatabase()->getTermArgTrie(eqc, d_op);
if( tat ){
//create an equivalence class iterator in eq class eqc
Node rep = ee->getRepresentative( eqc );
d_eqc_iter = eq::EqClassIterator( rep, ee );
d_mode = cand_term_eqc;
}else{
d_mode = cand_term_none;
}
}else{
//the only match is this term itself
d_eqc = eqc;
d_mode = cand_term_ident;
}
}
}
}
bool CandidateGeneratorQE::isLegalOpCandidate( Node n ) {
if( n.hasOperator() ){
if( isLegalCandidate( n ) ){
return d_qe->getTermDatabase()->getMatchOperator( n )==d_op;
}
}
return false;
}
Node CandidateGeneratorQE::getNextCandidate(){
if( d_mode==cand_term_db ){
Debug("cand-gen-qe") << "...get next candidate in tbd" << std::endl;
//get next candidate term in the uf term database
while( d_term_iter<d_term_iter_limit ){
Node n = d_qe->getTermDatabase()->getGroundTerm( d_op, d_term_iter );
d_term_iter++;
if( isLegalCandidate( n ) ){
if( d_qe->getTermDatabase()->hasTermCurrent( n ) ){
if( d_exclude_eqc.empty() ){
return n;
}else{
Node r = d_qe->getEqualityQuery()->getRepresentative( n );
if( d_exclude_eqc.find( r )==d_exclude_eqc.end() ){
Debug("cand-gen-qe") << "...returning " << n << std::endl;
return n;
}
}
}
}
}
}else if( d_mode==cand_term_eqc ){
Debug("cand-gen-qe") << "...get next candidate in eqc" << std::endl;
while( !d_eqc_iter.isFinished() ){
Node n = *d_eqc_iter;
++d_eqc_iter;
if( isLegalOpCandidate( n ) ){
Debug("cand-gen-qe") << "...returning " << n << std::endl;
return n;
}
}
}else if( d_mode==cand_term_ident ){
Debug("cand-gen-qe") << "...get next candidate identity" << std::endl;
if (!d_eqc.isNull())
{
Node n = d_eqc;
d_eqc = Node::null();
if( isLegalOpCandidate( n ) ){
return n;
}
}
}
return Node::null();
}
CandidateGeneratorQELitDeq::CandidateGeneratorQELitDeq( QuantifiersEngine* qe, Node mpat ) :
CandidateGenerator( qe ), d_match_pattern( mpat ){
Assert( d_match_pattern.getKind()==EQUAL );
d_match_pattern_type = d_match_pattern[0].getType();
}
void CandidateGeneratorQELitDeq::reset( Node eqc ){
Node false_term = d_qe->getEqualityQuery()->getEngine()->getRepresentative( NodeManager::currentNM()->mkConst<bool>(false) );
d_eqc_false = eq::EqClassIterator( false_term, d_qe->getEqualityQuery()->getEngine() );
}
Node CandidateGeneratorQELitDeq::getNextCandidate(){
//get next candidate term in equivalence class
while( !d_eqc_false.isFinished() ){
Node n = (*d_eqc_false);
++d_eqc_false;
if( n.getKind()==d_match_pattern.getKind() ){
if( n[0].getType().isComparableTo( d_match_pattern_type ) ){
//found an iff or equality, try to match it
//DO_THIS: cache to avoid redundancies?
//DO_THIS: do we need to try the symmetric equality for n? or will it also exist in the eq class of false?
return n;
}
}
}
return Node::null();
}
CandidateGeneratorQEAll::CandidateGeneratorQEAll( QuantifiersEngine* qe, Node mpat ) :
CandidateGenerator( qe ), d_match_pattern( mpat ){
d_match_pattern_type = mpat.getType();
Assert( mpat.getKind()==INST_CONSTANT );
d_f = quantifiers::TermUtil::getInstConstAttr( mpat );
d_index = mpat.getAttribute(InstVarNumAttribute());
d_firstTime = false;
}
void CandidateGeneratorQEAll::reset( Node eqc ) {
d_eq = eq::EqClassesIterator( d_qe->getEqualityQuery()->getEngine() );
d_firstTime = true;
}
Node CandidateGeneratorQEAll::getNextCandidate() {
while( !d_eq.isFinished() ){
TNode n = (*d_eq);
++d_eq;
if( n.getType().isComparableTo( d_match_pattern_type ) ){
TNode nh = d_qe->getTermDatabase()->getEligibleTermInEqc( n );
if( !nh.isNull() ){
if( options::instMaxLevel()!=-1 || options::lteRestrictInstClosure() ){
nh = d_qe->getInternalRepresentative( nh, d_f, d_index );
//don't consider this if already the instantiation is ineligible
if( !d_qe->getTermDatabase()->isTermEligibleForInstantiation( nh, d_f, false ) ){
nh = Node::null();
}
}
if( !nh.isNull() ){
d_firstTime = false;
//an equivalence class with the same type as the pattern, return it
return nh;
}
}
}
}
if( d_firstTime ){
//must return something
d_firstTime = false;
return d_qe->getInstantiate()->getTermForType(d_match_pattern_type);
}
return Node::null();
}
CandidateGeneratorConsExpand::CandidateGeneratorConsExpand(
QuantifiersEngine* qe, Node mpat)
: CandidateGeneratorQE(qe, mpat)
{
Assert(mpat.getKind() == APPLY_CONSTRUCTOR);
d_mpat_type = static_cast<DatatypeType>(mpat.getType().toType());
}
void CandidateGeneratorConsExpand::reset(Node eqc)
{
d_term_iter = 0;
if (eqc.isNull())
{
d_mode = cand_term_db;
}
else
{
d_eqc = eqc;
d_mode = cand_term_ident;
Assert(d_eqc.getType().toType() == d_mpat_type);
}
}
Node CandidateGeneratorConsExpand::getNextCandidate()
{
// get the next term from the base class
Node curr = CandidateGeneratorQE::getNextCandidate();
if (curr.isNull() || (curr.hasOperator() && curr.getOperator() == d_op))
{
return curr;
}
// expand it
NodeManager* nm = NodeManager::currentNM();
std::vector<Node> children;
const Datatype& dt = d_mpat_type.getDatatype();
Assert(dt.getNumConstructors() == 1);
children.push_back(d_op);
for (unsigned i = 0, nargs = dt[0].getNumArgs(); i < nargs; i++)
{
Node sel =
nm->mkNode(APPLY_SELECTOR_TOTAL,
Node::fromExpr(dt[0].getSelectorInternal(d_mpat_type, i)),
curr);
children.push_back(sel);
}
return nm->mkNode(APPLY_CONSTRUCTOR, children);
}
bool CandidateGeneratorConsExpand::isLegalOpCandidate(Node n)
{
return isLegalCandidate(n);
}
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