lemon/lp_skeleton.h
author Peter Kovacs <kpeter@inf.elte.hu>
Tue, 15 Mar 2011 19:32:21 +0100
changeset 936 ddd3c0d3d9bf
parent 746 e4554cd6b2bf
child 1063 1782aa72495a
permissions -rw-r--r--
Implement the scaling Price Refinement heuristic in CostScaling (#417)
instead of Early Termination.

These two heuristics are similar, but the newer one is faster
and not only makes it possible to skip some epsilon phases, but
it can improve the performance of the other phases, as well.
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/* -*- mode: C++; indent-tabs-mode: nil; -*-
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 *
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 * This file is a part of LEMON, a generic C++ optimization library.
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 *
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 * Copyright (C) 2003-2010
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 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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 * (Egervary Research Group on Combinatorial Optimization, EGRES).
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 *
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 * Permission to use, modify and distribute this software is granted
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 * provided that this copyright notice appears in all copies. For
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 * precise terms see the accompanying LICENSE file.
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 *
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 * This software is provided "AS IS" with no warranty of any kind,
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 * express or implied, and with no claim as to its suitability for any
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 * purpose.
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 *
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 */
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#ifndef LEMON_LP_SKELETON_H
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#define LEMON_LP_SKELETON_H
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#include <lemon/lp_base.h>
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///\file
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///\brief Skeleton file to implement LP/MIP solver interfaces
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///
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///The classes in this file do nothing, but they can serve as skeletons when
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///implementing an interface to new solvers.
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namespace lemon {
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  ///A skeleton class to implement LP/MIP solver base interface
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  ///This class does nothing, but it can serve as a skeleton when
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  ///implementing an interface to new solvers.
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  class SkeletonSolverBase : public virtual LpBase {
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    int col_num,row_num;
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  protected:
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    SkeletonSolverBase()
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      : col_num(-1), row_num(-1) {}
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    /// \e
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    virtual int _addCol();
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    /// \e
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    virtual int _addRow();
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    /// \e
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    virtual int _addRow(Value l, ExprIterator b, ExprIterator e, Value u);
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    /// \e
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    virtual void _eraseCol(int i);
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    /// \e
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    virtual void _eraseRow(int i);
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    /// \e
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    virtual void _getColName(int col, std::string& name) const;
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    /// \e
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    virtual void _setColName(int col, const std::string& name);
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    /// \e
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    virtual int _colByName(const std::string& name) const;
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    /// \e
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    virtual void _getRowName(int row, std::string& name) const;
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    /// \e
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    virtual void _setRowName(int row, const std::string& name);
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    /// \e
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    virtual int _rowByName(const std::string& name) const;
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    /// \e
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    virtual void _setRowCoeffs(int i, ExprIterator b, ExprIterator e);
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    /// \e
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    virtual void _getRowCoeffs(int i, InsertIterator b) const;
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    /// \e
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    virtual void _setColCoeffs(int i, ExprIterator b, ExprIterator e);
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    /// \e
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    virtual void _getColCoeffs(int i, InsertIterator b) const;
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    /// Set one element of the coefficient matrix
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    virtual void _setCoeff(int row, int col, Value value);
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    /// Get one element of the coefficient matrix
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    virtual Value _getCoeff(int row, int col) const;
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    /// The lower bound of a variable (column) have to be given by an
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    /// extended number of type Value, i.e. a finite number of type
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    /// Value or -\ref INF.
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    virtual void _setColLowerBound(int i, Value value);
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    /// \e
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    /// The lower bound of a variable (column) is an
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    /// extended number of type Value, i.e. a finite number of type
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    /// Value or -\ref INF.
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    virtual Value _getColLowerBound(int i) const;
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    /// The upper bound of a variable (column) have to be given by an
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    /// extended number of type Value, i.e. a finite number of type
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    /// Value or \ref INF.
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    virtual void _setColUpperBound(int i, Value value);
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    /// \e
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    /// The upper bound of a variable (column) is an
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    /// extended number of type Value, i.e. a finite number of type
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    /// Value or \ref INF.
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    virtual Value _getColUpperBound(int i) const;
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    /// The lower bound of a constraint (row) have to be given by an
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    /// extended number of type Value, i.e. a finite number of type
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    /// Value or -\ref INF.
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    virtual void _setRowLowerBound(int i, Value value);
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    /// \e
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    /// The lower bound of a constraint (row) is an
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    /// extended number of type Value, i.e. a finite number of type
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    /// Value or -\ref INF.
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    virtual Value _getRowLowerBound(int i) const;
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    /// The upper bound of a constraint (row) have to be given by an
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    /// extended number of type Value, i.e. a finite number of type
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    /// Value or \ref INF.
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    virtual void _setRowUpperBound(int i, Value value);
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    /// \e
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    /// The upper bound of a constraint (row) is an
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    /// extended number of type Value, i.e. a finite number of type
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    /// Value or \ref INF.
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    virtual Value _getRowUpperBound(int i) const;
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    /// \e
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    virtual void _setObjCoeffs(ExprIterator b, ExprIterator e);
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    /// \e
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    virtual void _getObjCoeffs(InsertIterator b) const;
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    /// \e
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    virtual void _setObjCoeff(int i, Value obj_coef);
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    /// \e
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    virtual Value _getObjCoeff(int i) const;
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    ///\e
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    virtual void _setSense(Sense);
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    ///\e
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    virtual Sense _getSense() const;
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    ///\e
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    virtual void _clear();
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    ///\e
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    virtual void _messageLevel(MessageLevel);
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  };
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  /// \brief Skeleton class for an LP solver interface
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  ///
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  ///This class does nothing, but it can serve as a skeleton when
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  ///implementing an interface to new solvers.
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  ///\ingroup lp_group
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  class LpSkeleton : public LpSolver, public SkeletonSolverBase {
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  public:
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    ///\e
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    LpSkeleton() : LpSolver(), SkeletonSolverBase() {}
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    ///\e
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    virtual LpSkeleton* newSolver() const;
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    ///\e
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    virtual LpSkeleton* cloneSolver() const;
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  protected:
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    ///\e
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    virtual SolveExitStatus _solve();
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    ///\e
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    virtual Value _getPrimal(int i) const;
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    ///\e
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    virtual Value _getDual(int i) const;
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    ///\e
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    virtual Value _getPrimalValue() const;
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    ///\e
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    virtual Value _getPrimalRay(int i) const;
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    ///\e
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    virtual Value _getDualRay(int i) const;
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    ///\e
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    virtual ProblemType _getPrimalType() const;
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    ///\e
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    virtual ProblemType _getDualType() const;
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    ///\e
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    virtual VarStatus _getColStatus(int i) const;
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    ///\e
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    virtual VarStatus _getRowStatus(int i) const;
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    ///\e
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    virtual const char* _solverName() const;
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  };
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  /// \brief Skeleton class for a MIP solver interface
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  ///
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  ///This class does nothing, but it can serve as a skeleton when
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  ///implementing an interface to new solvers.
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  ///\ingroup lp_group
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  class MipSkeleton : public MipSolver, public SkeletonSolverBase {
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  public:
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    ///\e
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    MipSkeleton() : MipSolver(), SkeletonSolverBase() {}
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    ///\e
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    virtual MipSkeleton* newSolver() const;
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    ///\e
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    virtual MipSkeleton* cloneSolver() const;
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  protected:
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    ///\e
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    virtual SolveExitStatus _solve();
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    ///\e
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    virtual Value _getSol(int i) const;
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    ///\e
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    virtual Value _getSolValue() const;
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    ///\e
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    virtual ProblemType _getType() const;
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    ///\e
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    virtual const char* _solverName() const;
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  };
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} //namespace lemon
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#endif