Coulomb_ExchangeEval.h

/*-------------------------------------------------------------------
Copyright 2012 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_CORE_COULOMB_EXCHANGEEVAL_H
#define JDFTX_CORE_COULOMB_EXCHANGEEVAL_H

#include <core/Coulomb.h>
#include <core/Coulomb_internal.h>

struct ExchangeEval
{
        ExchangeEval(const GridInfo& gInfo, const CoulombParams& params, const Coulomb& coulomb, double omega);
        ~ExchangeEval();
        complexScalarFieldTilde operator()(complexScalarFieldTilde&& in, vector3<> kDiff) const;

private:
        const GridInfo& gInfo;
        double omega;
        
        //Shorthand for combinations of regularization method and geometry
        enum KernelMode
        {       PeriodicKernel, //regularization = None/AuxiliaryFunction/ProbeChargeEwald, with geometry = Periodic
                SphericalKernel, //regularization = SphericalTruncated, or regularization = None and geometry = Spherical
                SlabKernel, //regularization = None/AuxiliaryFunction/ProbeChargeEwald with geometry = Slab
                WignerSeitzGammaKernel, //regularization = None and geometry = Isolated
                NumericalKernel //regularization = WignerSeitzTruncated, or regularization = None/AuxiliaryFunction/ProbeChargeEwald with geometry = Wire/Cylinder
        } kernelMode;
        
        //For all analytic modes (None, AuxiliaryFunction, SphericalTruncated):
        double Vzero; //G=0 term (0, the auxiliary correction, and the G=0 limit respectively)
        //For spherical mode
        double Rc;
        ExchangeSphericalScreened_calc sphericalScreenedCalc; //for screened exchange
        //For slab mode:
        ExchangeSlab_calc slabCalc;
        //For Wigner-Seitz Gamma-only truncated mode:
        RealKernel* VcGamma; //Gamma-point-only kernel (used for Isolated geometry (with no need for regularization))
        //For precomputed numerical kernel mode:
        std::vector< vector3<> > dkArr; //list of allowed k-point differences (modulo integer offsets)
        double* kernelData; //data for all the kernels (either on the CPU or GPU, as appropriate)
};

#endif // JDFTX_CORE_COULOMB_EXCHANGEEVAL_H