spxgeometsc.h

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/*                  This file is part of the class library                   */
/*       SoPlex --- the Sequential object-oriented simPlex.                  */
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/*    Copyright (C) 1996-2019 Konrad-Zuse-Zentrum                            */
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/**@file  spxgeometsc.h
 * @brief LP geometric mean scaling.
 */
#ifndef _SPXGEOMETSC_H_
#define _SPXGEOMETSC_H_

#include <assert.h>

#include "soplex/spxdefines.h"
#include "soplex/spxscaler.h"

namespace soplex
{
/**@brief Geometric mean row/column scaling.
   @ingroup Algo

   This SPxScaler implementation performs geometric mean scaling of the
   LPs rows and columns.
*/
class SPxGeometSC : public SPxScaler
{
protected:

   //-------------------------------------
   /**@name Data */
   //@{
   const bool postequilibration;  ///< equilibrate after geometric scaling?
   const int  m_maxIterations;    ///< maximum number of scaling iterations.
   const Real
   m_minImprovement;   ///< improvement necessary to carry on. (Bixby said Fourer said in MP 23, 274 ff. that 0.9 is a good value)
   const Real m_goodEnoughRatio;  ///< no scaling needed if ratio is less than this.
   //@}

public:

   //-------------------------------------
   /**@name Construction / destruction */
   //@{
   /// default constructor (this scaler makes no use of inherited members m_colFirst and m_doBoth)
   explicit SPxGeometSC(bool equilibrate = false, int maxIters = 8, Real minImpr = 0.85,
                        Real goodEnough = 1e3);
   /// copy constructor
   SPxGeometSC(const SPxGeometSC& old);
   /// assignment operator
   SPxGeometSC& operator=(const SPxGeometSC&);
   /// destructor
   virtual ~SPxGeometSC()
   {}
   /// clone function for polymorphism
   inline virtual SPxScaler* clone() const override
   {
      return new SPxGeometSC(*this);
   }
   //@}

   //-------------------------------------
   /**@name Scaling */
   //@{
   /// Scale the loaded SPxLP.
   virtual void scale(SPxLPBase<Real>& lp, bool persistent = true) override;
   //@}

};
} // namespace soplex
#endif // _SPXGEOMETSC_H_