src/theory/valuation.h

   1 /*********************                                                        */
   2 /*! \file valuation.h
   3  ** \verbatim
   4  ** Top contributors (to current version):
   5  **   Morgan Deters, Dejan Jovanovic, Andrew Reynolds
   6  ** This file is part of the CVC4 project.
   7  ** Copyright (c) 2009-2016 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.\endverbatim
  11  **
  12  ** \brief A "valuation" proxy for TheoryEngine
  13  **
  14  ** A "valuation" proxy for TheoryEngine.  This class breaks the dependence
  15  ** of theories' getValue() implementations on TheoryEngine.  getValue()
  16  ** takes a Valuation, which delegates to TheoryEngine.
  17  **/
  18
  19 #include "cvc4_private.h"
  20
  21 #ifndef __CVC4__THEORY__VALUATION_H
  22 #define __CVC4__THEORY__VALUATION_H
  23
  24 #include "expr/node.h"
  25 #include "options/theoryof_mode.h"
  26
  27 namespace CVC4 {
  28
  29 class TheoryEngine;
  30
  31 namespace theory {
  32
  33 class EntailmentCheckParameters;
  34 class EntailmentCheckSideEffects;
  35 class TheoryModel;
  36
  37 /**
  38  * The status of an equality in the current context.
  39  */
  40 enum EqualityStatus {
  41   /** The equality is known to be true and has been propagated */
  42   EQUALITY_TRUE_AND_PROPAGATED,
  43   /** The equality is known to be false and has been propagated */
  44   EQUALITY_FALSE_AND_PROPAGATED,
  45   /** The equality is known to be true */
  46   EQUALITY_TRUE,
  47   /** The equality is known to be false */
  48   EQUALITY_FALSE,
  49   /** The equality is not known, but is true in the current model */
  50   EQUALITY_TRUE_IN_MODEL,
  51   /** The equality is not known, but is false in the current model */
  52   EQUALITY_FALSE_IN_MODEL,
  53   /** The equality is completely unknown */
  54   EQUALITY_UNKNOWN
  55 };/* enum EqualityStatus */
  56
  57 /**
  58  * Returns true if the two statuses are compatible, i.e. both TRUE
  59  * or both FALSE (regardless of inmodel/propagation).
  60  */
  61 bool equalityStatusCompatible(EqualityStatus s1, EqualityStatus s2);
  62
  63 class Valuation {
  64   TheoryEngine* d_engine;
  65 public:
  66   Valuation(TheoryEngine* engine) :
  67     d_engine(engine) {
  68   }
  69
  70   /**
  71    * Return true if n has an associated SAT literal
  72    */
  73   bool isSatLiteral(TNode n) const;
  74
  75   /**
  76    * Get the current SAT assignment to the node n.
  77    *
  78    * This is only permitted if n is a theory atom that has an associated
  79    * SAT literal (or its negation).
  80    *
  81    * @return Node::null() if no current assignment; otherwise true or false.
  82    */
  83   Node getSatValue(TNode n) const;
  84
  85   /**
  86    * Returns true if the node has a current SAT assignment. If yes, the
  87    * argument "value" is set to its value.
  88    *
  89    * This is only permitted if n is a theory atom that has an associated
  90    * SAT literal.
  91    *
  92    * @return true if the literal has a current assignment, and returns the
  93    * value in the "value" argument; otherwise false and the "value"
  94    * argument is unmodified.
  95    */
  96   bool hasSatValue(TNode n, bool& value) const;
  97
  98   /**
  99    * Returns the equality status of the two terms, from the theory that owns the domain type.
 100    * The types of a and b must be the same.
 101    */
 102   EqualityStatus getEqualityStatus(TNode a, TNode b);
 103
 104   /**
 105    * Returns the model value of the shared term (or null if not available).
 106    */
 107   Node getModelValue(TNode var);
 108
 109   /**
 110    * Returns pointer to model.
 111    */
 112   TheoryModel* getModel();
 113
 114   /**
 115    * Ensure that the given node will have a designated SAT literal
 116    * that is definitionally equal to it.  The result of this function
 117    * is a Node that can be queried via getSatValue().
 118    *
 119    * @return the actual node that's been "literalized," which may
 120    * differ from the input due to theory-rewriting and preprocessing,
 121    * as well as CNF conversion
 122    */
 123   Node ensureLiteral(TNode n) CVC4_WARN_UNUSED_RESULT;
 124
 125   /**
 126    * Returns whether the given lit (which must be a SAT literal) is a decision
 127    * literal or not.  Throws an exception if lit is not a SAT literal.  "lit" may
 128    * be in either phase; that is, if "lit" is a SAT literal, this function returns
 129    * true both for lit and the negation of lit.
 130    */
 131   bool isDecision(Node lit) const;
 132
 133   /**
 134    * Get the assertion level of the SAT solver.
 135    */
 136   unsigned getAssertionLevel() const;
 137
 138   /**
 139    * Request an entailment check according to the given theoryOfMode.
 140    * See theory.h for documentation on entailmentCheck().
 141    */
 142   std::pair<bool, Node> entailmentCheck(theory::TheoryOfMode mode, TNode lit, const theory::EntailmentCheckParameters* params = NULL, theory::EntailmentCheckSideEffects* out = NULL);
 143
 144   /** need check ? */
 145   bool needCheck() const;
 146
 147 };/* class Valuation */
 148
 149 }/* CVC4::theory namespace */
 150 }/* CVC4 namespace */
 151
 152 #endif /* __CVC4__THEORY__VALUATION_H */