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// $Id: CbcBranchToFixLots.hpp 1899 2013-04-09 18:12:08Z stefan $
// 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).
// Edwin 11/13/2009-- carved out of CbcBranchCut
#ifndef CbcBranchToFixLots_H
#define CbcBranchToFixLots_H
#include "CbcBranchCut.hpp"
#include "CbcBranchBase.hpp"
#include "OsiRowCut.hpp"
#include "CoinPackedMatrix.hpp"
/** Define a branch class that branches so that one way variables are fixed
while the other way cuts off that solution.
a) On reduced cost
b) When enough ==1 or <=1 rows have been satisfied (not fixed - satisfied)
*/
class CbcBranchToFixLots : public CbcBranchCut {
public:
// Default Constructor
CbcBranchToFixLots ();
/** Useful constructor - passed reduced cost tolerance and fraction we would like fixed.
Also depth level to do at.
Also passed number of 1 rows which when clean triggers fix
Always does if all 1 rows cleaned up and number>0 or if fraction columns reached
Also whether to create branch if can't reach fraction.
*/
CbcBranchToFixLots (CbcModel * model, double djTolerance,
double fractionFixed, int depth,
int numberClean = 0,
const char * mark = NULL,
bool alwaysCreate = false);
// Copy constructor
CbcBranchToFixLots ( const CbcBranchToFixLots &);
/// Clone
virtual CbcObject * clone() const;
// Assignment operator
CbcBranchToFixLots & operator=( const CbcBranchToFixLots& rhs);
// Destructor
~CbcBranchToFixLots ();
/** Does a lot of the work,
Returns 0 if no good, 1 if dj, 2 if clean, 3 if both
FIXME: should use enum or equivalent to make these numbers clearer.
*/
int shallWe() const;
/// Infeasibility for an integer variable - large is 0.5, but also can be infinity when known infeasible.
virtual double infeasibility(const OsiBranchingInformation * info,
int &preferredWay) const;
/** \brief Return true if object can take part in normal heuristics
*/
virtual bool canDoHeuristics() const {
return true;
}
/// Creates a branching object
virtual CbcBranchingObject * createCbcBranch(OsiSolverInterface * solver, const OsiBranchingInformation * info, int way) ;
/// Redoes data when sequence numbers change
virtual void redoSequenceEtc(CbcModel * model, int numberColumns, const int * originalColumns);
protected:
/// data
/// Reduced cost tolerance i.e. dj has to be >= this before fixed
double djTolerance_;
/// We only need to make sure this fraction fixed
double fractionFixed_;
/// Never fix ones marked here
char * mark_;
/// Matrix by row
CoinPackedMatrix matrixByRow_;
/// Do if depth multiple of this
int depth_;
/// number of ==1 rows which need to be clean
int numberClean_;
/// If true then always create branch
bool alwaysCreate_;
};
#endif
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