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/******************************************************************************
* Top contributors (to current version):
* Yancheng Ou
*
* This file is part of the cvc5 project.
*
* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
* in the top-level source directory and their institutional affiliations.
* All rights reserved. See the file COPYING in the top-level source
* directory for licensing information.
* ****************************************************************************
*
* The base class for optimizers of individual cvc5 type.
*/
#ifndef CVC5__OMT__OMT_OPTIMIZER_H
#define CVC5__OMT__OMT_OPTIMIZER_H
#include "smt/optimization_solver.h"
namespace cvc5::omt {
/**
* The base class for optimizers of individual CVC type
*/
class OMTOptimizer
{
public:
virtual ~OMTOptimizer() = default;
/**
* Given a target node, retrieve an optimizer specific for the node's type
* the second field isSigned specifies whether we should use signed comparison
* for BitVectors and it's only valid when the type is BitVector
*
* @param targetNode the target node for the expression to be optimized
* @param isSigned speficies whether to use signed comparison for BitVectors
* and it's only valid when the type of targetNode is BitVector
* @return a unique_pointer pointing to a derived class of OMTOptimizer
* and this is the optimizer for targetNode
**/
static std::unique_ptr<OMTOptimizer> getOptimizerForNode(
Node targetNode, bool isSigned = false);
/**
* Initialize an SMT subsolver for offline optimization purpose
* @param parentSMTSolver the parental solver containing the assertions
* @param needsTimeout specifies whether it needs timeout for each single
* query
* @param timeout the timeout value, given in milliseconds (ms)
* @return a unique_pointer of SMT subsolver
**/
static std::unique_ptr<SmtEngine> createOptCheckerWithTimeout(
SmtEngine* parentSMTSolver,
bool needsTimeout = false,
unsigned long timeout = 0);
/**
* Minimize the target node with constraints encoded in parentSMTSolver
*
* @param parentSMTSolver an SMT solver encoding the assertions as the
* constraints
* @param target the target expression to optimize
* @return pair<OptResult, Node>: the result of optimization and the optimized
* value, if OptResult is OPT_UNKNOWN, value returned could be empty node or
* something suboptimal.
**/
virtual std::pair<smt::OptResult, Node> minimize(SmtEngine* parentSMTSolver,
Node target) = 0;
/**
* Maximize the target node with constraints encoded in parentSMTSolver
*
* @param parentSMTSolver an SMT solver encoding the assertions as the
* constraints
* @param target the target expression to optimize
* @return pair<OptResult, Node>: the result of optimization and the optimized
* value, if OptResult is OPT_UNKNOWN, value returned could be empty node or
* something suboptimal.
**/
virtual std::pair<smt::OptResult, Node> maximize(SmtEngine* parentSMTSolver,
Node target) = 0;
};
} // namespace cvc5::omt
#endif /* CVC5__OMT__OMT_OPTIMIZER_H */
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