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/****************************************************************************** |
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* Top contributors (to current version): |
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* Andrew Reynolds, Mathias Preiner, Gereon Kremer |
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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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* Utility for blocking the current model. |
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*/ |
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#include "cvc5_private.h" |
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#ifndef __CVC5__THEORY__MODEL_BLOCKER_H |
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#define __CVC5__THEORY__MODEL_BLOCKER_H |
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#include <vector> |
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#include "expr/node.h" |
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#include "options/smt_options.h" |
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#include "smt/env_obj.h" |
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namespace cvc5 { |
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namespace theory { |
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class TheoryModel; |
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} |
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/** |
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* A utility for blocking the current model. |
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*/ |
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class ModelBlocker : protected EnvObj |
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{ |
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public: |
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ModelBlocker(Env& e); |
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/** get model blocker |
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* |
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* This returns a disjunction of literals ~L1 V ... V ~Ln with the following |
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* properties: |
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* (1) L1 ... Ln hold in the current model (given by argument m), |
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* (2) if mode is set to "literals", L1 ... Ln are literals that occur in |
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* assertions and propositionally entail all non-unit top-level assertions. |
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* (3) if mode is set to "values", L1 ... Ln are literals of the form x=c, |
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* where c is the value of x in the current model. |
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* (4) if exprToBlock is not empty, L1 ... Ln are literals of the form t=c, |
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* where c is the value of t in the current model. If exprToBlock is |
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* non-empty, then L1 ... Ln are t1=c1 ... tn=cn where exprToBlock is |
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* { t1 ... tn }; if exprToBlock is empty, then t1 ... tn are the free |
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* variables of assertions. |
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* |
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* We expect exprToBlock to be non-empty only if mode is |
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* BlockModelsMode::VALUES. |
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* |
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* For example, if our input is: |
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* x > 0 ^ ( y < 0 V z < 0 V w < 0 ) |
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* and m is { x -> 1, y -> 2, z -> -1, w -> -1 }, then this method may |
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* return ~(z < 0) or ~(w < 0) when set to mode "literals". |
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* |
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* Notice that we do not require that L1...Ln entail unit top-level assertions |
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* since these literals are trivially entailed to be true in all models of |
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* our input. In other words, we do not return ~(x < 0) V ~(w < 0) since the |
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* left disjunct is always false. |
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*/ |
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Node getModelBlocker( |
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const std::vector<Node>& assertions, |
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theory::TheoryModel* m, |
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options::BlockModelsMode mode, |
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const std::vector<Node>& exprToBlock = std::vector<Node>()); |
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}; /* class TheoryModelCoreBuilder */ |
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} // namespace cvc5 |
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#endif /* __CVC5__THEORY__MODEL_BLOCKER_H */ |