IonicMinimizer.h

/*-------------------------------------------------------------------
Copyright 2011 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
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(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
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-------------------------------------------------------------------*/

#ifndef JDFTX_ELECTRONIC_IONICMINIMIZER_H
#define JDFTX_ELECTRONIC_IONICMINIMIZER_H

#include <electronic/common.h>
#include <electronic/RadialFunction.h>
#include <core/Minimize.h>
#include <core/vector3.h>
#include <core/matrix3.h>
#include <vector>

struct IonicGradient : std::vector< std::vector< vector3<> > >
{
        void init(const IonInfo&); 
        void print(const Everything&, FILE*, const char* prefix="force") const;
        
        IonicGradient& operator*=(double);
        IonicGradient& operator+=(const IonicGradient&);
        
        IonicGradient operator*(double) const;
        IonicGradient operator+(const IonicGradient&) const;
        IonicGradient operator-(const IonicGradient&) const;
};

void axpy(double alpha, const IonicGradient& x, IonicGradient& y); 
double dot(const IonicGradient& x, const IonicGradient& y); 
IonicGradient clone(const IonicGradient& x); 
void randomize(IonicGradient& x); 

IonicGradient operator*(const matrix3<>&, const IonicGradient&); 


class IonicMinimizer : public Minimizable<IonicGradient>
{       Everything& e;
        
public:
        IonicMinimizer(Everything& e);
        //Virtual functions from Minimizable:
        void step(const IonicGradient& dir, double alpha);
        double compute(IonicGradient* grad, IonicGradient* Kgrad);
        bool report(int iter);
        void constrain(IonicGradient&);
        static const double maxAtomTestDisplacement; //maximum allowed atom displacement in test step
        static const double maxWfnsDragDisplacement; //maximum atom displacement for which wavefunction drag is allowed
        double safeStepSize(const IonicGradient& dir) const; //enforces IonicMinimizer::maxAtomTestDisplacement on test step size
        double sync(double x) const; 
        
        double minimize(const MinimizeParams& params); 
private:
        bool populationAnalysisPending; 
        bool skipWfnsDrag; 
};

#endif // JDFTX_ELECTRONIC_IONICMINIMIZER_H