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/********************* */
/*! \file quant_split.cpp
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds, Mathias Preiner, Morgan Deters
** This file is part of the CVC4 project.
** Copyright (c) 2009-2021 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 dynamic quantifiers splitting
**/
#include "theory/quantifiers/quant_split.h"
#include "expr/dtype.h"
#include "expr/dtype_cons.h"
#include "theory/quantifiers/term_database.h"
#include "theory/quantifiers/first_order_model.h"
#include "options/quantifiers_options.h"
using namespace CVC5::kind;
namespace CVC5 {
namespace theory {
namespace quantifiers {
QuantDSplit::QuantDSplit(QuantifiersState& qs,
QuantifiersInferenceManager& qim,
QuantifiersRegistry& qr,
TermRegistry& tr)
: QuantifiersModule(qs, qim, qr, tr), d_added_split(qs.getUserContext())
{
}
void QuantDSplit::checkOwnership(Node q)
{
// If q is non-standard (marked as sygus, quantifier elimination, etc.), then
// do no split it.
QAttributes qa;
QuantAttributes::computeQuantAttributes(q, qa);
if (!qa.isStandard())
{
return;
}
bool takeOwnership = false;
bool doSplit = false;
QuantifiersBoundInference& qbi = d_qreg.getQuantifiersBoundInference();
Trace("quant-dsplit-debug") << "Check split quantified formula : " << q << std::endl;
for( unsigned i=0; i<q[0].getNumChildren(); i++ ){
TypeNode tn = q[0][i].getType();
if( tn.isDatatype() ){
const DType& dt = tn.getDType();
if (dt.isRecursiveSingleton(tn))
{
Trace("quant-dsplit-debug") << "Datatype " << dt.getName() << " is recursive singleton." << std::endl;
}
else
{
if (options::quantDynamicSplit() == options::QuantDSplitMode::AGG)
{
// split if it is a finite datatype
doSplit = dt.isInterpretedFinite(tn);
}
else if (options::quantDynamicSplit()
== options::QuantDSplitMode::DEFAULT)
{
if (!qbi.isFiniteBound(q, q[0][i]))
{
if (dt.isInterpretedFinite(tn))
{
// split if goes from being unhandled -> handled by finite
// instantiation. An example is datatypes with uninterpreted sort
// fields which are "interpreted finite" but not "finite".
doSplit = true;
// we additionally take ownership of this formula, in other words,
// we mark it reduced.
takeOwnership = true;
}
else if (dt.getNumConstructors() == 1 && !dt.isCodatatype())
{
// split if only one constructor
doSplit = true;
}
}
}
if (doSplit)
{
// store the index to split
d_quant_to_reduce[q] = i;
Trace("quant-dsplit-debug")
<< "Split at index " << i << " based on datatype " << dt.getName()
<< std::endl;
break;
}
Trace("quant-dsplit-debug")
<< "Do not split based on datatype " << dt.getName() << std::endl;
}
}
}
if (takeOwnership)
{
Trace("quant-dsplit-debug") << "Will take ownership." << std::endl;
d_qreg.setOwner(q, this);
}
// Notice we may not take ownership in some cases, meaning that both the
// original quantified formula and the split one are generated. This may
// increase our ability to answer "unsat", since quantifier instantiation
// heuristics may be more effective for one or the other (see issues #993
// and 3481).
}
/* whether this module needs to check this round */
bool QuantDSplit::needsCheck( Theory::Effort e ) {
return e>=Theory::EFFORT_FULL && !d_quant_to_reduce.empty();
}
bool QuantDSplit::checkCompleteFor( Node q ) {
// true if we split q
return d_added_split.find( q )!=d_added_split.end();
}
/* Call during quantifier engine's check */
void QuantDSplit::check(Theory::Effort e, QEffort quant_e)
{
//add lemmas ASAP (they are a reduction)
if (quant_e != QEFFORT_CONFLICT)
{
return;
}
Trace("quant-dsplit") << "QuantDSplit::check" << std::endl;
NodeManager* nm = NodeManager::currentNM();
FirstOrderModel* m = d_treg.getModel();
std::vector<Node> lemmas;
for (std::map<Node, int>::iterator it = d_quant_to_reduce.begin();
it != d_quant_to_reduce.end();
++it)
{
Node q = it->first;
Trace("quant-dsplit") << "- Split quantifier " << q << std::endl;
if (m->isQuantifierAsserted(q) && m->isQuantifierActive(q)
&& d_added_split.find(q) == d_added_split.end())
{
d_added_split.insert(q);
std::vector<Node> bvs;
for (unsigned i = 0, nvars = q[0].getNumChildren(); i < nvars; i++)
{
if (static_cast<int>(i) != it->second)
{
bvs.push_back(q[0][i]);
}
}
std::vector<Node> disj;
disj.push_back(q.negate());
TNode svar = q[0][it->second];
TypeNode tn = svar.getType();
Assert(tn.isDatatype());
std::vector<Node> cons;
const DType& dt = tn.getDType();
for (unsigned j = 0, ncons = dt.getNumConstructors(); j < ncons; j++)
{
std::vector<Node> vars;
for (unsigned k = 0, nargs = dt[j].getNumArgs(); k < nargs; k++)
{
TypeNode tns = dt[j][k].getRangeType();
Node v = nm->mkBoundVar(tns);
vars.push_back(v);
}
std::vector<Node> bvs_cmb;
bvs_cmb.insert(bvs_cmb.end(), bvs.begin(), bvs.end());
bvs_cmb.insert(bvs_cmb.end(), vars.begin(), vars.end());
vars.insert(vars.begin(), dt[j].getConstructor());
Node c = nm->mkNode(kind::APPLY_CONSTRUCTOR, vars);
TNode ct = c;
Node body = q[1].substitute(svar, ct);
if (!bvs_cmb.empty())
{
Node bvl = nm->mkNode(kind::BOUND_VAR_LIST, bvs_cmb);
std::vector<Node> children;
children.push_back(bvl);
children.push_back(body);
if (q.getNumChildren() == 3)
{
Node ipls = q[2].substitute(svar, ct);
children.push_back(ipls);
}
body = nm->mkNode(kind::FORALL, children);
}
cons.push_back(body);
}
Node conc = cons.size() == 1 ? cons[0] : nm->mkNode(kind::AND, cons);
disj.push_back(conc);
lemmas.push_back(disj.size() == 1 ? disj[0] : nm->mkNode(kind::OR, disj));
}
}
// add lemmas to quantifiers engine
for (const Node& lem : lemmas)
{
Trace("quant-dsplit") << "QuantDSplit lemma : " << lem << std::endl;
d_qim.addPendingLemma(lem, InferenceId::QUANTIFIERS_DSPLIT);
}
Trace("quant-dsplit") << "QuantDSplit::check finished" << std::endl;
}
} // namespace quantifiers
} // namespace theory
} // namespace CVC5
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