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/********************* */
/*! \file inst_strategy_enumerative.h
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds
** This file is part of the CVC4 project.
** Copyright (c) 2009-2017 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 Enumerative instantiation
**/
#include "cvc4_private.h"
#ifndef __CVC4__INST_STRATEGY_ENUMERATIVE_H
#define __CVC4__INST_STRATEGY_ENUMERATIVE_H
#include "context/context.h"
#include "context/context_mm.h"
#include "theory/quantifiers_engine.h"
namespace CVC4 {
namespace theory {
namespace quantifiers {
/** Enumerative instantiation
*
* This class implements enumerative instantiation described
* in Reynolds et al., "Revisiting Enumerative Instantiation".
*
* It is an instance of QuantifiersModule, whose main
* task is to make calls to QuantifiersEngine during
* calls to QuantifiersModule::check(...).
*
* This class adds instantiations based on enumerating
* well-typed terms that occur in the current context
* based on a heuristically determined ordering on
* tuples of terms. This ordering incorporates
* reasoning about the relevant domain of quantified
* formulas (see theory/quantifiers/relevant_domain.h).
* We consider only ground terms that occur in the
* context due to Theorem 1 of "Revisiting Enumerative
* Instantiation". Notice this theorem holds only for theories
* with compactness. For theories such as arithmetic,
* this class may introduce "default" terms that are
* used in instantiations, say 0 for arithmetic, even
* when the term 0 does not occur in the context.
*
* This strategy is not enabled by default, and
* is enabled by the option:
* --full-saturate-quant
*
* It is generally called with lower priority than
* other instantiation strategies, although this
* option interleaves it with other strategies
* during quantifier effort level QEFFORT_STANDARD:
* --fs-interleave
*/
class InstStrategyEnum : public QuantifiersModule
{
public:
InstStrategyEnum(QuantifiersEngine* qe);
~InstStrategyEnum() {}
/** Needs check. */
bool needsCheck(Theory::Effort e) override;
/** Reset round. */
void reset_round(Theory::Effort e) override;
/** Check.
* Adds instantiations for all currently asserted
* quantified formulas via calls to process(...)
*/
void check(Theory::Effort e, QEffort quant_e) override;
/** Register quantifier. */
void registerQuantifier(Node q) override;
/** Identify. */
std::string identify() const override
{
return std::string("InstStrategyEnum");
}
private:
/** process quantified formula
*
* q is the quantified formula we are constructing instances for.
* fullEffort is whether we are called at full effort.
*
* If this function returns true, then one instantiation
* (determined by an enumeration) was added via a successful
* call to QuantifiersEngine::addInstantiation(...).
*
* If fullEffort is true, then we may introduce a "default"
* well-typed term *not* occurring in the current context.
* This handles corner cases where there are no well-typed
* ground terms in the current context to instantiate with.
*/
bool process(Node q, bool fullEffort);
}; /* class InstStrategyEnum */
} /* CVC4::theory::quantifiers namespace */
} /* CVC4::theory namespace */
} /* CVC4 namespace */
#endif
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