SCF.h

/*-------------------------------------------------------------------
Copyright 2013 Deniz Gunceler, Ravishankar Sundararaman

This file is part of JDFTx.

JDFTx 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 3 of the License, or
(at your option) any later version.

JDFTx 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 JDFTx.  If not, see <http://www.gnu.org/licenses/>.
-------------------------------------------------------------------*/

#ifndef JDFTX_ELECTRONIC_SCF_H
#define JDFTX_ELECTRONIC_SCF_H

#include <electronic/common.h>
#include <electronic/Everything.h>
#include <electronic/BandMinimizer.h>
#include <electronic/operators.h>
#include <core/Pulay.h>

struct SCFvariable
{       ScalarFieldArray n; 
        ScalarFieldArray tau; 
        std::vector<matrix> rhoAtom; 
};

class SCF : public Pulay<SCFvariable>
{
public:
        SCF(Everything& e);
        
        void minimize();
        
        static double eigDiffRMS(const std::vector<diagMatrix>&, const std::vector<diagMatrix>&, const Everything& e); 
        
protected:
        //---- Interface to Pulay ----
        double sync(double x) const;
        double cycle(double dEprev, std::vector<double>& extraValues);
        void report(int iter);
        void axpy(double alpha, const SCFvariable& X, SCFvariable& Y) const;
        double dot(const SCFvariable& X, const SCFvariable& Y) const;
        size_t variableSize() const;
        void readVariable(SCFvariable&, FILE*) const;
        void writeVariable(const SCFvariable&, FILE*) const;
        SCFvariable getVariable() const;
        void setVariable(const SCFvariable&);
        SCFvariable precondition(const SCFvariable&) const;
        SCFvariable applyMetric(const SCFvariable&) const;

private:
        Everything& e;
        bool mixTau; 
        RealKernel kerkerMix, diisMetric; 
        
        void updateFillings();
        void updateMOM();
        std::vector<ColumnBundle> Cold; // Wavefunctions from the previous iteration
        
        double eigDiffRMS(const std::vector<diagMatrix>&, const std::vector<diagMatrix>&) const; 
        void eigenShiftInit(); 
        void eigenShiftApply(bool reverse);  
};

#endif