Susceptibility.h

/* Copyright 2017 Kristofer Björnson
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef COM_DAFER45_TBTK_SOLVER_SUSCEPTIBILITY
#define COM_DAFER45_TBTK_SOLVER_SUSCEPTIBILITY

#include "TBTK/RPA/MomentumSpaceContext.h"

#include <complex>
#include <vector>

namespace TBTK{
namespace Solver{

class Susceptibility : public Solver{
public:
    enum Algorithm {
        Lindhard = 0,
        Matsubara = 1,
        RPA = 2
    };

    Susceptibility(
        Algorithm algorithm,
        const RPA::MomentumSpaceContext &momentumSpaceContext
    );

    virtual ~Susceptibility();

    virtual std::vector<std::complex<double>> calculateSusceptibility(
        const Index &index,
        const std::vector<std::complex<double>> &energies
    ) = 0;

    const RPA::MomentumSpaceContext& getMomentumSpaceContext() const;

    Algorithm getAlgorithm() const;

    void setEnergiesAreInversionSymmetric(
        bool energiesAreInversionSymmetric
    );

    bool getEnergiesAreInversionSymmetric() const;
private:
    Algorithm algorithm;

    bool energiesAreInversionSymmetric;

    const RPA::MomentumSpaceContext *momentumSpaceContext;
};

inline const RPA::MomentumSpaceContext& Susceptibility::getMomentumSpaceContext(
) const{
    return *momentumSpaceContext;
}

inline Susceptibility::Algorithm Susceptibility::getAlgorithm() const{
    return algorithm;
}

inline void Susceptibility::setEnergiesAreInversionSymmetric(
    bool energiesAreInversionSymmetric
){
    this->energiesAreInversionSymmetric = energiesAreInversionSymmetric;
}

inline bool Susceptibility::getEnergiesAreInversionSymmetric(
) const{
    return energiesAreInversionSymmetric;
}

};  //End of namespace Solver
};  //End of namespace TBTK

#endif