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/********************* */
/*! \file quant_split.h
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds, Mathias Preiner
** 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 dynamic quantifiers splitting
**/
#include "cvc4_private.h"
#ifndef CVC4__THEORY__QUANT_SPLIT_H
#define CVC4__THEORY__QUANT_SPLIT_H
#include "context/cdo.h"
#include "theory/quantifiers/quant_util.h"
namespace CVC4 {
namespace theory {
class QuantifiersEngine;
namespace quantifiers {
/** Quantifiers dynamic splitting
*
* This module identifies quantified formulas that should be "split", e.g.
* based on datatype constructor case splitting.
*
* An example of a quantified formula that we may split is the following. Let:
* optionPair := mkPair( U, U ) | none
* where U is an uninterpreted sort. The quantified formula:
* forall x : optionPair. P( x )
* may be "split" via the lemma:
* forall x : optionPair. P( x ) <=>
* ( forall xy : U. P( mkPair( x, y ) ) OR P( none ) )
*
* Notice that such splitting may lead to exponential behavior, say if we
* quantify over 32 variables of type optionPair above gives 2^32 disjuncts.
* This class is used to compute this splitting dynamically, by splitting
* one variable per quantified formula at a time.
*/
class QuantDSplit : public QuantifiersModule {
typedef context::CDHashSet<Node, NodeHashFunction> NodeSet;
public:
QuantDSplit( QuantifiersEngine * qe, context::Context* c );
/** determine whether this quantified formula will be reduced */
void checkOwnership(Node q) override;
/* whether this module needs to check this round */
bool needsCheck(Theory::Effort e) override;
/* Call during quantifier engine's check */
void check(Theory::Effort e, QEffort quant_e) override;
/** check complete for */
bool checkCompleteFor(Node q) override;
/** Identify this module (for debugging, dynamic configuration, etc..) */
std::string identify() const override { return "QuantDSplit"; }
private:
/** list of relevant quantifiers asserted in the current context */
std::map<Node, int> d_quant_to_reduce;
/** whether we have instantiated quantified formulas */
NodeSet d_added_split;
};
}
}
}
#endif
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