CbcBranchLotsize.hpp

/* $Id$ */
// Copyright (C) 2004, International Business Machines
// Corporation and others.  All Rights Reserved.
// This code is licensed under the terms of the Eclipse Public License (EPL).

#ifndef CbcBranchLotsize_H
#define CbcBranchLotsize_H

#include "CbcBranchBase.hpp"
/** Lotsize class */

class CbcLotsize : public CbcObject {

public:
  // Default Constructor
  CbcLotsize();

  /* Useful constructor - passed model index.
       Also passed valid values - if range then pairs
    */
  CbcLotsize(CbcModel *model, int iColumn,
    int numberPoints, const double *points, bool range = false);

  // Copy constructor
  CbcLotsize(const CbcLotsize &);

  /// Clone
  virtual CbcObject *clone() const;

  // Assignment operator
  CbcLotsize &operator=(const CbcLotsize &rhs);

  // Destructor
  ~CbcLotsize();

  /// Infeasibility - large is 0.5
  virtual double infeasibility(const OsiBranchingInformation *info,
    int &preferredWay) const;

  using CbcObject::feasibleRegion;
  /** Set bounds to contain the current solution.

      More precisely, for the variable associated with this object, take the
      value given in the current solution, force it within the current bounds
      if required, then set the bounds to fix the variable at the integer
      nearest the solution value.
    */
  virtual void feasibleRegion();

  /// Creates a branching object
  virtual CbcBranchingObject *createCbcBranch(OsiSolverInterface *solver, const OsiBranchingInformation *info, int way);

  /** \brief Given a valid solution (with reduced costs, etc.),
        return a branching object which would give a new feasible
        point in the good direction.

      The preferred branching object will force the variable to be +/-1 from
      its current value, depending on the reduced cost and objective sense.  If
      movement in the direction which improves the objective is impossible due
      to bounds on the variable, the branching object will move in the other
      direction.  If no movement is possible, the method returns NULL.

      Only the bounds on this variable are considered when determining if the new
      point is feasible.
    */
  virtual CbcBranchingObject *preferredNewFeasible() const;

  /** \brief Given a valid solution (with reduced costs, etc.),
        return a branching object which would give a new feasible
        point in a bad direction.

      As for preferredNewFeasible(), but the preferred branching object will
      force movement in a direction that degrades the objective.
    */
  virtual CbcBranchingObject *notPreferredNewFeasible() const;

  /** Reset original upper and lower bound values from the solver.

      Handy for updating bounds held in this object after bounds held in the
      solver have been tightened.
     */
  virtual void resetBounds(const OsiSolverInterface *solver);

  /** Finds range of interest so value is feasible in range range_ or infeasible
        between hi[range_] and lo[range_+1].  Returns true if feasible.
    */
  bool findRange(double value) const;

  /** Returns floor and ceiling
    */
  virtual void floorCeiling(double &floorLotsize, double &ceilingLotsize, double value,
    double tolerance) const;

  /// Model column number
  inline int modelSequence() const
  {
    return columnNumber_;
  }
  /// Set model column number
  inline void setModelSequence(int value)
  {
    columnNumber_ = value;
  }

  /** Column number if single column object -1 otherwise,
        so returns >= 0
        Used by heuristics
    */
  virtual int columnNumber() const;
  /// Original variable bounds
  inline double originalLowerBound() const
  {
    return bound_[0];
  }
  inline double originalUpperBound() const
  {
    return bound_[rangeType_ * numberRanges_ - 1];
  }
  /// Type - 1 points, 2 ranges
  inline int rangeType() const
  {
    return rangeType_;
  }
  /// Number of points
  inline int numberRanges() const
  {
    return numberRanges_;
  }
  /// Ranges
  inline double *bound() const
  {
    return bound_;
  }
  /** \brief Return true if object can take part in normal heuristics
    */
  virtual bool canDoHeuristics() const
  {
    return false;
  }

private:
  /// Just for debug (CBC_PRINT defined in CbcBranchLotsize.cpp)
  void printLotsize(double value, bool condition, int type) const;

private:
  /// data

  /// Column number in model
  int columnNumber_;
  /// Type - 1 points, 2 ranges
  int rangeType_;
  /// Number of points
  int numberRanges_;
  // largest gap
  double largestGap_;
  /// Ranges
  double *bound_;
  /// Current range
  mutable int range_;
};

/** Lotsize branching object

  This object can specify a two-way branch on an integer variable. For each
  arm of the branch, the upper and lower bounds on the variable can be
  independently specified.

  Variable_ holds the index of the integer variable in the integerVariable_
  array of the model.
*/

class CbcLotsizeBranchingObject : public CbcBranchingObject {

public:
  /// Default constructor
  CbcLotsizeBranchingObject();

  /** Create a lotsize floor/ceiling branch object

      Specifies a simple two-way branch. Let \p value = x*. One arm of the
      branch will be is lb <= x <= valid range below(x*), the other valid range above(x*) <= x <= ub.
      Specify way = -1 to set the object state to perform the down arm first,
      way = 1 for the up arm.
    */
  CbcLotsizeBranchingObject(CbcModel *model, int variable,
    int way, double value, const CbcLotsize *lotsize);

  /** Create a degenerate branch object

      Specifies a `one-way branch'. Calling branch() for this object will
      always result in lowerValue <= x <= upperValue. Used to fix in valid range
    */

  CbcLotsizeBranchingObject(CbcModel *model, int variable, int way,
    double lowerValue, double upperValue);

  /// Copy constructor
  CbcLotsizeBranchingObject(const CbcLotsizeBranchingObject &);

  /// Assignment operator
  CbcLotsizeBranchingObject &operator=(const CbcLotsizeBranchingObject &rhs);

  /// Clone
  virtual CbcBranchingObject *clone() const;

  /// Destructor
  virtual ~CbcLotsizeBranchingObject();

  using CbcBranchingObject::branch;
  /** \brief Sets the bounds for the variable according to the current arm
           of the branch and advances the object state to the next arm.
    */
  virtual double branch();

  using CbcBranchingObject::print;
  /** \brief Print something about branch - only if log level high
    */
  virtual void print();

  /** Return the type (an integer identifier) of \c this */
  virtual CbcBranchObjType type() const
  {
    return LotsizeBranchObj;
  }

  // LL: compareOriginalObject can be inherited from the CbcBranchingObject
  // since variable_ uniquely defines the lot sizing object.

  /** Compare the \c this with \c brObj. \c this and \c brObj must be os the
        same type and must have the same original object, but they may have
        different feasible regions.
        Return the appropriate CbcRangeCompare value (first argument being the
        sub/superset if that's the case). In case of overlap (and if \c
        replaceIfOverlap is true) replace the current branching object with one
        whose feasible region is the overlap.
     */
  virtual CbcRangeCompare compareBranchingObject(const CbcBranchingObject *brObj, const bool replaceIfOverlap = false);

protected:
  /// Lower [0] and upper [1] bounds for the down arm (way_ = -1)
  double down_[2];
  /// Lower [0] and upper [1] bounds for the up arm (way_ = 1)
  double up_[2];
};

#endif

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