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/****************************************************************************** |
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* Top contributors (to current version): |
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* Liana Hadarean, Tim King, Mathias Preiner |
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* |
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* This file is part of the cvc5 project. |
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* |
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* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS |
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* in the top-level source directory and their institutional affiliations. |
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* All rights reserved. See the file COPYING in the top-level source |
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* directory for licensing information. |
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* **************************************************************************** |
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* |
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* Bitvector theory. |
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*/ |
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#include "cvc5_private.h" |
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#ifndef CVC5__THEORY__BV__ABSTRACTION_H |
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#define CVC5__THEORY__BV__ABSTRACTION_H |
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#include <unordered_map> |
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#include <unordered_set> |
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#include "expr/node.h" |
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#include "theory/substitutions.h" |
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#include "util/statistics_stats.h" |
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namespace cvc5 { |
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namespace theory { |
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namespace bv { |
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typedef std::vector<TNode> ArgsVec; |
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class AbstractionModule { |
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using NodeVecMap = std::unordered_map<Node, std::vector<Node>>; |
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using NodeTNodeMap = std::unordered_map<Node, TNode>; |
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using TNodeTNodeMap = std::unordered_map<TNode, TNode>; |
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using NodeNodeMap = std::unordered_map<Node, Node>; |
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using TNodeNodeMap = std::unordered_map<Node, TNode>; |
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using TNodeSet = std::unordered_set<TNode>; |
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using IntNodeMap = std::unordered_map<unsigned, Node>; |
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using IndexMap = std::unordered_map<unsigned, unsigned>; |
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using SkolemMap = std::unordered_map<unsigned, std::vector<Node> >; |
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using SignatureMap = std::unordered_map<TNode, unsigned>; |
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struct Statistics { |
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SizeStat<NodeNodeMap> d_numFunctionsAbstracted; |
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IntStat d_numArgsSkolemized; |
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TimerStat d_abstractionTime; |
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Statistics(const std::string& name, const NodeNodeMap& functionsAbstracted); |
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}; |
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class ArgsTableEntry { |
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std::vector<ArgsVec> d_data; |
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unsigned d_arity; |
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public: |
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ArgsTableEntry(unsigned n) |
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: d_arity(n) |
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{} |
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ArgsTableEntry() |
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: d_arity(0) |
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{} |
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void addArguments(const ArgsVec& args); |
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typedef std::vector<ArgsVec>::iterator iterator; |
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iterator begin() { return d_data.begin(); } |
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iterator end() { return d_data.end(); } |
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unsigned getArity() { return d_arity; } |
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unsigned getNumEntries() { return d_data.size(); } |
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ArgsVec& getEntry(unsigned i) |
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{ |
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Assert(i < d_data.size()); |
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return d_data[i]; |
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} |
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}; |
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class ArgsTable { |
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std::unordered_map<TNode, ArgsTableEntry> d_data; |
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bool hasEntry(TNode signature) const; |
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public: |
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typedef std::unordered_map<TNode, ArgsTableEntry>::iterator iterator; |
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ArgsTable() {} |
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void addEntry(TNode signature, const ArgsVec& args); |
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ArgsTableEntry& getEntry(TNode signature); |
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iterator begin() { return d_data.begin(); } |
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iterator end() { return d_data.end(); } |
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}; |
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/** |
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* Checks if one pattern is a generalization of the other |
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* |
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* @param s |
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* @param t |
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* |
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* @return 1 if s :> t, 2 if s <: t, 0 if they equivalent and -1 if they are incomparable |
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*/ |
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static int comparePatterns(TNode s, TNode t); |
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class LemmaInstantiatior { |
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std::vector<TNode> d_functions; |
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std::vector<int> d_maxMatch; |
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ArgsTable& d_argsTable; |
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context::Context* d_ctx; |
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theory::SubstitutionMap d_subst; |
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TNode d_conflict; |
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std::vector<Node> d_lemmas; |
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void backtrack(std::vector<int>& stack); |
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int next(int val, int index); |
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bool isConsistent(const std::vector<int>& stack); |
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bool accept(const std::vector<int>& stack); |
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void mkLemma(); |
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public: |
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LemmaInstantiatior(const std::vector<TNode>& functions, ArgsTable& table, TNode conflict) |
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: d_functions(functions) |
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, d_argsTable(table) |
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, d_ctx(new context::Context()) |
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, d_subst(d_ctx) |
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, d_conflict(conflict) |
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, d_lemmas() |
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{ |
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Debug("bv-abstraction-gen") << "LemmaInstantiator conflict:" << conflict << "\n"; |
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// initializing the search space |
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for (unsigned i = 0; i < functions.size(); ++i) { |
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TNode func_op = functions[i].getOperator(); |
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// number of matches for this function |
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unsigned maxCount = table.getEntry(func_op).getNumEntries(); |
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d_maxMatch.push_back(maxCount); |
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} |
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} |
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void generateInstantiations(std::vector<Node>& lemmas); |
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}; |
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ArgsTable d_argsTable; |
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// mapping between signature and uninterpreted function symbol used to |
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// abstract the signature |
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NodeNodeMap d_signatureToFunc; |
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NodeNodeMap d_funcToSignature; |
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NodeNodeMap d_assertionToSignature; |
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SignatureMap d_signatures; |
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NodeNodeMap d_sigToGeneralization; |
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TNodeSet d_skolems; |
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// skolems maps |
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IndexMap d_signatureIndices; |
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SkolemMap d_signatureSkolems; |
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void collectArgumentTypes(TNode sig, std::vector<TypeNode>& types, TNodeSet& seen); |
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void collectArguments(TNode node, TNode sig, std::vector<Node>& args, TNodeSet& seen); |
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void finalizeSignatures(); |
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Node abstractSignatures(TNode assertion); |
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Node computeSignature(TNode node); |
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bool isConjunctionOfAtoms(TNode node, TNodeSet& seen); |
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TNode getGeneralization(TNode term); |
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void storeGeneralization(TNode s, TNode t); |
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// signature skolem stuff |
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Node getGeneralizedSignature(Node node); |
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Node getSignatureSkolem(TNode node); |
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unsigned getBitwidthIndex(unsigned bitwidth); |
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void resetSignatureIndex(); |
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Node computeSignatureRec(TNode, NodeNodeMap&); |
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void storeSignature(Node signature, TNode assertion); |
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bool hasSignature(Node node); |
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Node substituteArguments(TNode signature, TNode apply, unsigned& i, TNodeTNodeMap& seen); |
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// crazy instantiation methods |
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void generateInstantiations(unsigned current, |
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std::vector<ArgsTableEntry>& matches, |
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std::vector<std::vector<ArgsVec> >& instantiations, |
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std::vector<std::vector<ArgsVec> >& new_instantiations); |
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Node tryMatching(const std::vector<Node>& ss, const std::vector<TNode>& tt, TNode conflict); |
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void makeFreshArgs(TNode func, std::vector<Node>& fresh_args); |
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void makeFreshSkolems(TNode node, SubstitutionMap& map, SubstitutionMap& reverse_map); |
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void skolemizeArguments(std::vector<Node>& assertions); |
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Node reverseAbstraction(Node assertion, NodeNodeMap& seen); |
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TNodeSet d_addedLemmas; |
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TNodeSet d_lemmaAtoms; |
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TNodeSet d_inputAtoms; |
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void storeLemma(TNode lemma); |
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Statistics d_statistics; |
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public: |
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AbstractionModule(const std::string& name) |
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: d_argsTable(), |
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d_signatureToFunc(), |
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d_funcToSignature(), |
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d_assertionToSignature(), |
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d_signatures(), |
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d_sigToGeneralization(), |
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d_skolems(), |
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d_signatureIndices(), |
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d_signatureSkolems(), |
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d_addedLemmas(), |
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d_lemmaAtoms(), |
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d_inputAtoms(), |
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d_statistics(name + "abstraction::", d_signatureToFunc) |
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{ |
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} |
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/** |
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* returns true if there are new uninterepreted functions symbols in the output |
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* |
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* @param assertions |
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* @param new_assertions |
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* |
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* @return |
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*/ |
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bool applyAbstraction(const std::vector<Node>& assertions, std::vector<Node>& new_assertions); |
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/** |
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* Returns true if the node represents an abstraction predicate. |
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* @param node |
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* @return |
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*/ |
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bool isAbstraction(TNode node); |
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/** |
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* Returns the interpretation of the abstraction predicate. |
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* |
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* @param node |
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* @return |
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*/ |
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Node getInterpretation(TNode node); |
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Node simplifyConflict(TNode conflict); |
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void generalizeConflict(TNode conflict, std::vector<Node>& lemmas); |
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void addInputAtom(TNode atom); |
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bool isLemmaAtom(TNode node) const; |
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}; |
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} |
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} |
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} // namespace cvc5 |
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#endif |