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/********************* */
/*! \file abstraction.h
** \verbatim
** Original author: Liana Hadarean
** Major contributors: none
** Minor contributors (to current version): Morgan Deters
** This file is part of the CVC4 project.
** Copyright (c) 2009-2014 New York University and The University of Iowa
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief Bitvector theory.
**
** Bitvector theory.
**/
#include "cvc4_private.h"
#ifndef __CVC4__THEORY__BV__ABSTRACTION_H
#define __CVC4__THEORY__BV__ABSTRACTION_H
#include <ext/hash_map>
#include <ext/hash_set>
#include "expr/node.h"
#include "theory/substitutions.h"
#include "util/statistics_registry.h"
namespace CVC4 {
namespace theory {
namespace bv {
typedef std::vector<TNode> ArgsVec;
class AbstractionModule {
struct Statistics {
IntStat d_numFunctionsAbstracted;
IntStat d_numArgsSkolemized;
TimerStat d_abstractionTime;
Statistics();
~Statistics();
};
class ArgsTableEntry {
std::vector<ArgsVec> d_data;
unsigned d_arity;
public:
ArgsTableEntry(unsigned n)
: d_arity(n)
{}
ArgsTableEntry()
: d_arity(0)
{}
void addArguments(const ArgsVec& args);
typedef std::vector<ArgsVec>::iterator iterator;
iterator begin() { return d_data.begin(); }
iterator end() { return d_data.end(); }
unsigned getArity() { return d_arity; }
unsigned getNumEntries() { return d_data.size(); }
ArgsVec& getEntry(unsigned i ) { Assert (i < d_data.size()); return d_data[i]; }
};
class ArgsTable {
__gnu_cxx::hash_map<TNode, ArgsTableEntry, TNodeHashFunction > d_data;
bool hasEntry(TNode signature) const;
public:
typedef __gnu_cxx::hash_map<TNode, ArgsTableEntry, TNodeHashFunction >::iterator iterator;
ArgsTable() {}
void addEntry(TNode signature, const ArgsVec& args);
ArgsTableEntry& getEntry(TNode signature);
iterator begin() { return d_data.begin(); }
iterator end() { return d_data.end(); }
};
/**
* Checks if one pattern is a generalization of the other
*
* @param s
* @param t
*
* @return 1 if s :> t, 2 if s <: t, 0 if they equivalent and -1 if they are incomparable
*/
static int comparePatterns(TNode s, TNode t);
class LemmaInstantiatior {
std::vector<TNode> d_functions;
std::vector<int> d_maxMatch;
ArgsTable& d_argsTable;
context::Context* d_ctx;
theory::SubstitutionMap d_subst;
TNode d_conflict;
std::vector<Node> d_lemmas;
void backtrack(std::vector<int>& stack);
int next(int val, int index);
bool isConsistent(const std::vector<int>& stack);
bool accept(const std::vector<int>& stack);
void mkLemma();
public:
LemmaInstantiatior(const std::vector<TNode>& functions, ArgsTable& table, TNode conflict)
: d_functions(functions)
, d_argsTable(table)
, d_ctx(new context::Context())
, d_subst(d_ctx)
, d_conflict(conflict)
, d_lemmas()
{
Debug("bv-abstraction-gen") << "LemmaInstantiator conflict:" << conflict << "\n";
// initializing the search space
for (unsigned i = 0; i < functions.size(); ++i) {
TNode func_op = functions[i].getOperator();
// number of matches for this function
unsigned maxCount = table.getEntry(func_op).getNumEntries();
d_maxMatch.push_back(maxCount);
}
}
void generateInstantiations(std::vector<Node>& lemmas);
};
typedef __gnu_cxx::hash_map<Node, std::vector<Node>, NodeHashFunction> NodeVecMap;
typedef __gnu_cxx::hash_map<Node, TNode, NodeHashFunction> NodeTNodeMap;
typedef __gnu_cxx::hash_map<TNode, TNode, TNodeHashFunction> TNodeTNodeMap;
typedef __gnu_cxx::hash_map<Node, Node, NodeHashFunction> NodeNodeMap;
typedef __gnu_cxx::hash_map<Node, TNode, NodeHashFunction> TNodeNodeMap;
typedef __gnu_cxx::hash_set<TNode, TNodeHashFunction> TNodeSet;
typedef __gnu_cxx::hash_map<unsigned, Node> IntNodeMap;
typedef __gnu_cxx::hash_map<unsigned, unsigned> IndexMap;
typedef __gnu_cxx::hash_map<unsigned, std::vector<Node> > SkolemMap;
typedef __gnu_cxx::hash_map<TNode, unsigned, TNodeHashFunction > SignatureMap;
ArgsTable d_argsTable;
// mapping between signature and uninterpreted function symbol used to
// abstract the signature
NodeNodeMap d_signatureToFunc;
NodeNodeMap d_funcToSignature;
NodeNodeMap d_assertionToSignature;
SignatureMap d_signatures;
NodeNodeMap d_sigToGeneralization;
TNodeSet d_skolems;
// skolems maps
IndexMap d_signatureIndices;
SkolemMap d_signatureSkolems;
void collectArgumentTypes(TNode sig, std::vector<TypeNode>& types, TNodeSet& seen);
void collectArguments(TNode node, TNode sig, std::vector<Node>& args, TNodeSet& seen);
void finalizeSignatures();
Node abstractSignatures(TNode assertion);
Node computeSignature(TNode node);
bool isConjunctionOfAtoms(TNode node);
bool isConjunctionOfAtomsRec(TNode node, TNodeSet& seen);
TNode getGeneralization(TNode term);
void storeGeneralization(TNode s, TNode t);
// signature skolem stuff
Node getGeneralizedSignature(Node node);
Node getSignatureSkolem(TNode node);
unsigned getBitwidthIndex(unsigned bitwidth);
void resetSignatureIndex();
Node computeSignatureRec(TNode, NodeNodeMap&);
void storeSignature(Node signature, TNode assertion);
bool hasSignature(Node node);
Node substituteArguments(TNode signature, TNode apply, unsigned& i, TNodeTNodeMap& seen);
// crazy instantiation methods
void generateInstantiations(unsigned current,
std::vector<ArgsTableEntry>& matches,
std::vector<std::vector<ArgsVec> >& instantiations,
std::vector<std::vector<ArgsVec> >& new_instantiations);
Node tryMatching(const std::vector<Node>& ss, const std::vector<TNode>& tt, TNode conflict);
void makeFreshArgs(TNode func, std::vector<Node>& fresh_args);
void makeFreshSkolems(TNode node, SubstitutionMap& map, SubstitutionMap& reverse_map);
void skolemizeArguments(std::vector<Node>& assertions);
Node reverseAbstraction(Node assertion, NodeNodeMap& seen);
TNodeSet d_addedLemmas;
TNodeSet d_lemmaAtoms;
TNodeSet d_inputAtoms;
void storeLemma(TNode lemma);
Statistics d_statistics;
public:
AbstractionModule()
: d_argsTable()
, d_signatureToFunc()
, d_funcToSignature()
, d_assertionToSignature()
, d_signatures()
, d_sigToGeneralization()
, d_skolems()
, d_signatureIndices()
, d_signatureSkolems()
, d_addedLemmas()
, d_lemmaAtoms()
, d_inputAtoms()
, d_statistics()
{}
/**
* returns true if there are new uninterepreted functions symbols in the output
*
* @param assertions
* @param new_assertions
*
* @return
*/
bool applyAbstraction(const std::vector<Node>& assertions, std::vector<Node>& new_assertions);
/**
* Returns true if the node represents an abstraction predicate.
*
* @param node
*
* @return
*/
bool isAbstraction(TNode node);
/**
* Returns the interpretation of the abstraction predicate.
*
* @param node
*
* @return
*/
Node getInterpretation(TNode node);
Node simplifyConflict(TNode conflict);
void generalizeConflict(TNode conflict, std::vector<Node>& lemmas);
void addInputAtom(TNode atom);
bool isLemmaAtom(TNode node) const;
};
}
}
}
#endif
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