LatticeMinimizer.h

/*-------------------------------------------------------------------
Copyright 2012 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_LATTICEMINIMIZER_H
#define JDFTX_ELECTRONIC_LATTICEMINIMIZER_H

#include <electronic/common.h>
#include <core/Minimize.h>
#include <core/matrix3.h>

//Functions required by Minimizable<matrix3<>>
void axpy(double alpha, const matrix3<>& x, matrix3<>& y); 
double dot(const matrix3<>& x, const matrix3<>& y); 
matrix3<> clone(const matrix3<>& x); 
void randomize(matrix3<>& x); 

class LatticeMinimizer : public Minimizable<matrix3<>>
{
public:
        LatticeMinimizer(Everything&);
        
        //Virtual functions from Minimizable:
        void step(const matrix3<>& dir, double alpha);
        double compute(matrix3<>* grad, matrix3<>* Kgrad);
        bool report(int iter);
        void constrain(matrix3<>&);
        double safeStepSize(const matrix3<>& dir) const;
        double sync(double x) const; 

        std::vector<double> calculateStress();

        std::vector<matrix3<>> strainBasis;
        
        void restore();
        
private:
        Everything& e;
        matrix3<> Rorig; 
        matrix3<> strain; 
        bool skipWfnsDrag; 
        
        double h; 
        double centralDifference(matrix3<> direction);  
        
        static void updateLatticeDependent(Everything& e, bool ignoreElectronic=false);
        
        friend class IonDynamics;
};

#endif // JDFTX_ELECTRONIC_LATTICEMINIMIZER_H