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

#ifndef JDFTX_ELECTRONIC_EXCORR_H
#define JDFTX_ELECTRONIC_EXCORR_H

#include <electronic/common.h>
#include <core/ScalarFieldArray.h>

enum ExCorrType
{
        ExCorrLDA_PZ, 
        ExCorrLDA_PW, 
        ExCorrLDA_PW_prec, 
        ExCorrLDA_VWN, 
        ExCorrLDA_Teter, 
        ExCorrGGA_PBE, 
        ExCorrGGA_PBEsol, 
        ExCorrGGA_PW91, 
        ExCorrMGGA_TPSS, 
        ExCorrMGGA_revTPSS, 
#ifdef LIBXC_ENABLED
        ExCorrLibXC,
#endif
        ExCorrORB_GLLBsc, 
        ExCorrPOT_LB94, 
        ExCorrHYB_PBE0, 
        ExCorrHYB_HSE06, 
        ExCorrHYB_HSE12, 
        ExCorrHYB_HSE12s, 
        ExCorrHF 
};

enum KineticType
{
#ifdef LIBXC_ENABLED
        KineticLibXC,
#endif
        KineticNone, 
        KineticTF, 
        KineticVW, 
        KineticPW91 
};

struct IncludeTXC
{       bool T; 
        bool X; 
        bool C; 
        
        IncludeTXC(bool T=false, bool X=true, bool C=true) : T(T), X(X), C(C) {} 
};

class ExCorr
{
public:
        ExCorr(ExCorrType exCorrType=ExCorrGGA_PBE, KineticType kineticType=KineticNone); 
        void setup(const Everything&); 
        string getName() const; 
        
        double operator()(const ScalarFieldArray& n, ScalarFieldArray* Vxc=0, IncludeTXC includeTXC=IncludeTXC(),
                const ScalarFieldArray* tau=0, ScalarFieldArray* Vtau=0) const;
        
        double operator()(const ScalarField& n, ScalarField* Vxc=0, IncludeTXC includeTXC=IncludeTXC(),
                const ScalarField* tau=0, ScalarField* Vtau=0) const;

        double exxFactor() const; 
        double exxRange() const; 
        bool needsKEdensity() const; 
        bool hasEnergy() const; 
        
        void getSecondDerivatives(const ScalarField& n, ScalarField& e_nn, ScalarField& e_sigma, ScalarField& e_nsigma, ScalarField& e_sigmasigma, double nCut=1e-4) const;
        
        struct OrbitalDep
        {       OrbitalDep(const Everything& e) : e(e) {}
                virtual ~OrbitalDep() {}
                virtual bool ignore_nCore() const=0; 
                virtual ScalarFieldArray getPotential() const=0; 
                virtual void dump() const=0; 
        protected:
                const Everything& e;
        };
        std::shared_ptr<OrbitalDep> orbitalDep; //optional orbital-dependent potential functional
        
private:
        const Everything* e;
        ExCorrType exCorrType;
        KineticType kineticType;
        string xcName; // short name of the functional (set by command elec-ex-corr)
        friend struct CommandElecExCorr;
        friend struct CommandFluidExCorr;
        
        double exxScale; //scale factor for exact exchange
        double exxOmega; //Range parameter for exact exchange
        std::shared_ptr<struct FunctionalList> functionals; //List of component functionals
#ifdef LIBXC_ENABLED
        int xcExchange, xcCorr, xcExcorr, xcKinetic; //LibXC codes for various functional components (0 if unused)
#endif
};

#endif // JDFTX_ELECTRONIC_EXCORR_H