CouenneExprMultiLin.hpp

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/* $Id: CouenneExprMultiLin.hpp 615 2011-06-08 20:36:24Z pbelotti $
 *
 * Name:    CouenneExprMultilin.hpp
 * Author:  Pietro Belotti
 * Purpose: Multilinear terms
 *
 * This file is licensed under the Eclipse Public License (EPL)
 */

#ifndef COUENNE_EXPRMULTILIN_H
#define COUENNE_EXPRMULTILIN_H

#include <vector>

#include "CouenneExprOp.hpp"

namespace Couenne {


  class exprMultiLin: public exprMul {

  public:

    exprMultiLin (expression **, int);

    exprMultiLin (expression *, expression *);

    CouNumber gradientNorm (const double *x);

    expression *differentiate (int index); 

    expression *simplify ();

    virtual int Linearity ();

    virtual void getBounds (expression *&, expression *&);

    virtual void getBounds (CouNumber &lb, CouNumber &ub);

    virtual exprAux *standardize (CouenneProblem *p, bool addAux = true);

    void generateCuts (expression *w, //const OsiSolverInterface &si, 
                       OsiCuts &cs, const CouenneCutGenerator *cg, 
                       t_chg_bounds * = NULL, int = -1, 
                       CouNumber = -COUENNE_INFINITY, 
                       CouNumber =  COUENNE_INFINITY);

    virtual enum expr_type code () 
    {return COU_EXPRMUL;}

    bool impliedBound (int, CouNumber *, CouNumber *, t_chg_bounds *, enum Couenne::expression::auxSign = Couenne::expression::AUX_EQ);

    virtual CouNumber selectBranch (const CouenneObject *obj, 
                                    const OsiBranchingInformation *info,
                                    expression * &var, 
                                    double * &brpts, 
                                    double * &brDist, // distance of current LP
                                    // point to new convexifications
                                    int &way);

    virtual void closestFeasible (expression *varind,
                                  expression *vardep,
                                  CouNumber &left,
                                  CouNumber &right) const;
  protected:

    int impliedBoundMul (CouNumber wl, 
                         CouNumber wu, 
                         std::vector <CouNumber> &xl,
                         std::vector <CouNumber> &xu,
                         std::vector <std::pair <int, CouNumber> > &nl,
                         std::vector <std::pair <int, CouNumber> > &nu);

    CouNumber balancedMul (const OsiBranchingInformation *info, int index, int wind);

    virtual bool isCuttable (CouenneProblem *problem, int index) const
    {return false;} // concave on both sides, as for products
  };
}

#endif