DMRGSCFintegrals.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 DMRGSCFINTEGRALS_CHEMPS2_H
#define DMRGSCFINTEGRALS_CHEMPS2_H

#include "DMRGSCFindices.h"

namespace CheMPS2{
   class DMRGSCFintegrals{

      public:
      

         DMRGSCFintegrals(DMRGSCFindices * iHandler);
         
         virtual ~DMRGSCFintegrals();
         
         void clear();
         

         void set_coulomb(const int Ic1, const int Ic2, const int Ia1, const int Ia2, const int c1, const int c2, const int a1, const int a2, const double val);


         void add_coulomb(const int Ic1, const int Ic2, const int Ia1, const int Ia2, const int c1, const int c2, const int a1, const int a2, const double val);


         double get_coulomb(const int Ic1, const int Ic2, const int Ia1, const int Ia2, const int c1, const int c2, const int a1, const int a2) const;


         void set_exchange(const int Ic1, const int Ic2, const int Iv1, const int Iv2, const int c1, const int c2, const int v1, const int v2, const double val);
         

         void add_exchange(const int Ic1, const int Ic2, const int Iv1, const int Iv2, const int c1, const int c2, const int v1, const int v2, const double val);
         

         double get_exchange(const int Ic1, const int Ic2, const int Iv1, const int Iv2, const int c1, const int c2, const int v1, const int v2) const;
         

         double FourIndexAPI(const int I1, const int I2, const int I3, const int I4, const int index1, const int index2, const int index3, const int index4) const;
      
      private:
      
         // The number of irreps
         int numberOfIrreps;
         
         // The number of core orbitals per irrep
         int * NCORE;
         
         // The number of virtual orbitals per irrep
         int * NVIRTUAL;
         
         // The total number of orbitals per irrep
         int * NTOTAL;
         
         // Pointers to the Coulomb array:
         //    - coulomb_ptr[ Ic1 x Ic2 != 0 ][ I_c1 ][ I_a1 ][ c1 + size(c1) * c2 ] points to the relevant part of coulomb_array
         //    - coulomb_ptr[ Ic1 x Ic2 == 0 ][ I_c1 ][ I_a1 ][ c1 + (c2*(c2+1))/2 ] points to the relevant part of coulomb_array
         long long **** coulomb_ptr;
         long long coulomb_size;
         double * coulomb_array;
         long long calcNumCoulombElements(const bool allocate);
         long long get_coulomb_ptr( const int Ic1, const int Ic2, const int Ia1, const int Ia2, const int c1, const int c2, const int a1, const int a2 ) const;
         
         // Pointers to the Exchange array:
         //    - exchange_ptr[ Ic1 x Ic2 != 0 ][ I_c1 ][ I_v1 ][ c1 + size(c1) * c2 ] points to the relevant part of exchange_array
         //    - exchange_ptr[ Ic1 x Ic2 == 0 ][ I_c1 ][ I_v1 ][ c1 + (c2*(c2+1))/2 ] points to the relevant part of exchange_array
         long long **** exchange_ptr;
         long long exchange_size;
         double * exchange_array;
         long long calcNumExchangeElements(const bool allocate);
         long long get_exchange_ptr( const int Ic1, const int Ic2, const int Iv1, const int Iv2, const int c1, const int c2, const int v1, const int v2 ) const;

   };
}

#endif