Correlations.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 CORRELATIONS_CHEMPS2_H
#define CORRELATIONS_CHEMPS2_H

#include "SyBookkeeper.h"
#include "Problem.h"
#include "TwoDM.h"
#include "TensorGYZ.h"
#include "TensorKM.h"

namespace CheMPS2{
   class Correlations{

      public:
      

         Correlations(const SyBookkeeper * denBKIn, const Problem * ProbIn, TwoDM * the2DMin);
         
         virtual ~Correlations();
         

         double getCspin_DMRG(const int row, const int col) const;


         double getCspin_HAM(const int row, const int col) const;


         double getCdens_DMRG(const int row, const int col) const;
         

         double getCdens_HAM(const int row, const int col) const;


         double getCspinflip_DMRG(const int row, const int col) const;


         double getCspinflip_HAM(const int row, const int col) const;
         

         double getCdirad_DMRG(const int row, const int col) const;


         double getCdirad_HAM(const int row, const int col) const;


         double getMutualInformation_DMRG(const int row, const int col) const;


         double getMutualInformation_HAM(const int row, const int col) const;
         

         double SingleOrbitalEntropy_DMRG(const int index) const;
         

         double SingleOrbitalEntropy_HAM(const int index) const;
         

         void FillSite(TensorT * denT, TensorGYZ ** Gtensors, TensorGYZ ** Ytensors, TensorGYZ ** Ztensors, TensorKM ** Ktensors, TensorKM ** Mtensors);
         

         double MutualInformationDistance(const double power) const;
         

         void Print(const int precision=6, const int columnsPerLine=8) const;
         
         void mpi_broadcast();
         
      private:
      
         //The BK containing all the irrep information
         const SyBookkeeper * denBK;
         
         //The problem containing orbital reshuffling and symmetry information
         const Problem * Prob;
         
         //The 2-RDM of the active space
         TwoDM * the2DM;
         
         //The number of active space orbitals
         int L;
         
         //The spin correlation function
         double * Cspin;
         
         //The density correlation function
         double * Cdens;
         
         //The spin-flip correlation function
         double * Cspinflip;
         
         //The singlet diradical correlation function
         double * Cdirad;
         
         //The two-orbital mutual information
         double * MutInfo;
         
         //Helper function: fills Cspin, Cdens, Cspinflip, and Cdirad (the latter only partially)
         void FillSpinDensSpinflip();
         
         //Helper functions for FillSite
         double diagram1(TensorT * denT, TensorGYZ * denY, double * workmem) const;
         double diagram2(TensorT * denT, TensorGYZ * denZ, double * workmem) const;
         double diagram3(TensorT * denT, TensorGYZ * denG, double * workmem) const;
         double diagram4(TensorT * denT, TensorKM * denK, double * workmem) const;
         double diagram5(TensorT * denT, TensorKM * denM, double * workmem) const;
         
         //Helper function to print tables in a nice format
         void PrintTableNice(const double * table, const int sPrecision, const int columnsPerLine) const;
         
   };
}

#endif