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       1                 :            : /******************************************************************************
       2                 :            :  * Top contributors (to current version):
       3                 :            :  *   Andrew Reynolds, Mathias Preiner, Aina Niemetz
       4                 :            :  *
       5                 :            :  * This file is part of the cvc5 project.
       6                 :            :  *
       7                 :            :  * Copyright (c) 2009-2024 by the authors listed in the file AUTHORS
       8                 :            :  * in the top-level source directory and their institutional affiliations.
       9                 :            :  * All rights reserved.  See the file COPYING in the top-level source
      10                 :            :  * directory for licensing information.
      11                 :            :  * ****************************************************************************
      12                 :            :  *
      13                 :            :  * Equality query class.
      14                 :            :  */
      15                 :            : 
      16                 :            : #include "cvc5_private.h"
      17                 :            : 
      18                 :            : #ifndef CVC5__THEORY__QUANTIFIERS_EQUALITY_QUERY_H
      19                 :            : #define CVC5__THEORY__QUANTIFIERS_EQUALITY_QUERY_H
      20                 :            : 
      21                 :            : #include "context/cdo.h"
      22                 :            : #include "context/context.h"
      23                 :            : #include "expr/node.h"
      24                 :            : #include "theory/quantifiers/quant_util.h"
      25                 :            : 
      26                 :            : namespace cvc5::internal {
      27                 :            : namespace theory {
      28                 :            : namespace quantifiers {
      29                 :            : 
      30                 :            : class FirstOrderModel;
      31                 :            : class QuantifiersState;
      32                 :            : 
      33                 :            : /** EqualityQuery class
      34                 :            :  *
      35                 :            :  * The main method of this class is the function
      36                 :            :  * getInternalRepresentative, which is used by instantiation-based methods
      37                 :            :  * that are agnostic with respect to choosing terms within an equivalence class.
      38                 :            :  * Examples of such methods are finite model finding and enumerative
      39                 :            :  * instantiation. Method getInternalRepresentative returns the "best"
      40                 :            :  * representative based on the internal heuristic, which is currently based on
      41                 :            :  * choosing the term that was previously chosen as a representative earliest.
      42                 :            :  */
      43                 :            : class EqualityQuery : public QuantifiersUtil
      44                 :            : {
      45                 :            :  public:
      46                 :            :   EqualityQuery(Env& env, QuantifiersState& qs, FirstOrderModel* m);
      47                 :            :   virtual ~EqualityQuery();
      48                 :            : 
      49                 :            :   /** reset */
      50                 :            :   bool reset(Theory::Effort e) override;
      51                 :            :   /* Called for new quantifiers */
      52                 :      57896 :   void registerQuantifier(Node q) override {}
      53                 :            :   /** identify */
      54                 :          0 :   std::string identify() const override { return "EqualityQuery"; }
      55                 :            :   /** gets the current best representative in the equivalence
      56                 :            :    * class of a, based on some heuristic. Currently, the default heuristic
      57                 :            :    * chooses terms that were previously chosen as representatives
      58                 :            :    * on the earliest instantiation round.
      59                 :            :    *
      60                 :            :    * If q is non-null, then q/index is the quantified formula
      61                 :            :    * and variable position that we are choosing for instantiation.
      62                 :            :    *
      63                 :            :    * This function avoids certain terms that are "ineligible" for instantiation.
      64                 :            :    * If cbqi is active, we terms that contain instantiation constants
      65                 :            :    * are ineligible. As a result, this function may return
      66                 :            :    * Node::null() if all terms in the equivalence class of a
      67                 :            :    * are ineligible.
      68                 :            :    */
      69                 :            :   Node getInternalRepresentative(Node a, Node q, size_t index);
      70                 :            : 
      71                 :            :  private:
      72                 :            :   /** the quantifiers state */
      73                 :            :   QuantifiersState& d_qstate;
      74                 :            :   /** Pointer to the model */
      75                 :            :   FirstOrderModel* d_model;
      76                 :            :   /** quantifiers equality inference */
      77                 :            :   context::CDO<unsigned> d_eqi_counter;
      78                 :            :   /** internal representatives */
      79                 :            :   std::map< TypeNode, std::map< Node, Node > > d_int_rep;
      80                 :            :   /** rep score */
      81                 :            :   std::map<Node, int32_t> d_rep_score;
      82                 :            :   /** the number of times reset( e ) has been called */
      83                 :            :   size_t d_reset_count;
      84                 :            :   /** processInferences : will merge equivalence classes in master equality engine, if possible */
      85                 :            :   bool processInferences( Theory::Effort e );
      86                 :            :   /** node contains */
      87                 :            :   Node getInstance(Node n,
      88                 :            :                    const std::vector<Node>& eqc,
      89                 :            :                    std::unordered_map<TNode, Node>& cache);
      90                 :            :   /** get score */
      91                 :            :   int32_t getRepScore(Node n, Node f, size_t index, TypeNode v_tn);
      92                 :            : }; /* EqualityQuery */
      93                 :            : 
      94                 :            : }  // namespace quantifiers
      95                 :            : }  // namespace theory
      96                 :            : }  // namespace cvc5::internal
      97                 :            : 
      98                 :            : #endif /* CVC5__THEORY__QUANTIFIERS_EQUALITY_QUERY_H */