Blip.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
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
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-------------------------------------------------------------------*/

#ifndef JDFTX_ELECTRONIC_BLIP_H
#define JDFTX_ELECTRONIC_BLIP_H

#include <core/ScalarField.h>
#include <core/vector3.h>
#include <core/WignerSeitz.h>

//PW to blip conversion utility
//To use, create an object:
//      BlipConverter convert(Nx,Ny,Nz);
//and conversions can be done as:
//      vBlip = convert(vPW);
class BlipConverter
{
        vector3<int> S;
        std::vector<double> gamma[3];
public:
        BlipConverter(const vector3<int>& S);

        //Given a PW basis object (in real or reciprocal space) v,
        //return corresponding real-space Blip coefficient set
        // (for double or complex vectors)
        ScalarField operator()(const ScalarFieldTilde& v) const;
        ScalarField operator()(const ScalarField& v) const;
        complexScalarField operator()(const complexScalarFieldTilde& v) const;
        complexScalarField operator()(const complexScalarField& v) const;
};

class BlipResampler
{       const GridInfo& gInfoOut;
        BlipConverter converter;
        WignerSeitz wsIn;
        WignerSeitz wsOut;
public:
        BlipResampler(const GridInfo& gInfoIn, const GridInfo& gInfoOut);
        
        ScalarField operator()(const ScalarFieldTilde& v) const;
        complexScalarField operator()(const complexScalarFieldTilde& v) const;
};

//Compute the kinetic energy for a blip orbital phi (and set max local KE and location in unit cell)
double Tblip(const complexScalarField& phi, double* tMax=0, int* i0max=0, int* i1max=0, int*i2max=0);

//Compute the local potential energy for blip orbital phi in blip potential V
double Vblip(const complexScalarField& phi, const ScalarField& V);

#endif // JDFTX_ELECTRONIC_BLIP_H