DIIS.h

/*
   CheMPS2: a spin-adapted implementation of DMRG for ab initio quantum chemistry
   Copyright (C) 2013-2016 Sebastian Wouters

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with this program; if not, write to the Free Software Foundation, Inc.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#ifndef DIIS_CHEMPS2_H
#define DIIS_CHEMPS2_H

#include "Options.h"

namespace CheMPS2{
   class DIIS{

      public:
      

         DIIS(const int numVarsParamIn, const int numVarsErrorIn, const int numVecsIn);
         
         virtual ~DIIS();
         

         int getNumVarsParam() const;
         

         int getNumVarsError() const;
         

         int getNumVecs() const;
         

         int getCurrentNumVecs() const;
         

         double * getLastLinco();
         

         void appendNew(double * newError, double * newParam);
         

         void calculateParam(double * newParam);
         

         void saveDIIS(const string filename=DMRGSCF_diis_storage_name) const;
         

         void loadDIIS(const string filename=DMRGSCF_diis_storage_name);

      private:

         //The number of variables in the parameter vectors
         int numVarsParam;
         
         //The number of variables in the error vectors
         int numVarsError;
         
         //The max. number of vectors which should be kept
         int numVecs;
         
         //The current number of vectors in this object
         int currentNumVecs;
      
         //The error vectors
         double ** errorVectors;
         
         //The parameter vectors
         double ** paramVectors;
         
         //The last linco of parameter vectors
         double * lastLinco;
         
   };
}

#endif