SelfEnergyCalculator.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_SELF_ENERGY_CALCULATOR
#define COM_DAFER45_TBTK_SELF_ENERGY_CALCULATOR

#include "TBTK/BrillouinZone.h"
#include "TBTK/IndexedDataTree.h"
#include "TBTK/RPA/ElectronFluctuationVertexCalculator.h"

namespace TBTK{

class SelfEnergyCalculator{
public:
    SelfEnergyCalculator(
        const RPA::MomentumSpaceContext &momentumSpaceContext,
        unsigned int numWorkers
    );

    ~SelfEnergyCalculator();

    const RPA::MomentumSpaceContext& getMomentumSpaceContext() const;

    void init();

//  enum class EnergyType {Real, Imaginary, Complex};

    void setNumSummationEnergies(unsigned int numSummationEnergies);

//  void setEnergyType(EnergyType energyType);

//  EnergyType getEnergyType() const;

    void setSelfEnergyEnergies(
        const std::vector<std::complex<double>> &selfEnergyEnergies
    );

    std::vector<std::complex<double>> calculateSelfEnergy(
        const std::vector<double> &k,
        const std::vector<int> &orbitalIndices
    );

    std::vector<std::complex<double>> calculateSelfEnergySelfConsistently(
        unsigned int numMatsubaraFrequencies
    );

    void setU(std::complex<double> U);

    void setUp(std::complex<double> Up);

    void setJ(std::complex<double> J);

    void setJp(std::complex<double> Jp);

//  void precomputeSusceptibilities(unsigned int numWorkers = 128);

    void saveSusceptibilities(const std::string &filename) const;

    void loadSusceptibilities(const std::string &filename);
private:
    std::vector<ElectronFluctuationVertexCalculator*> electronFluctuationVertexCalculators;

    int *kMinusQLookupTable;

    void generateKMinusQLookupTable();

    template<bool useKPlusKLookupTable>
    int getKMinusQLinearIndex(
        unsigned int meshIndex,
        const std::vector<double> &k,
        int kLinearIndex
    ) const;

    unsigned int numSummationEnergies;

    std::vector<std::complex<double>> summationEnergies;

//  EnergyType energyType;

    std::vector<std::complex<double>> selfEnergyEnergies;

    bool isInitialized;

    IndexedDataTree<SerializableVector<std::complex<double>>> selfEnergyTree;

    template<bool singleSelfEnergyEnergy>
    void selfEnergyMainLoop(
        const std::vector<double> &k,
        const std::vector<int> &orbitalIndices,
        std::vector<std::complex<double>> &result
    );

    std::complex<double> U, Up, J, Jp;
};

inline const RPA::MomentumSpaceContext& SelfEnergyCalculator::getMomentumSpaceContext(
) const{
    return electronFluctuationVertexCalculators[0]->getMomentumSpaceContext();
}

inline void SelfEnergyCalculator::setNumSummationEnergies(
    unsigned int numSummationEnergies
){
    this->numSummationEnergies = numSummationEnergies;
}

/*inline void SelfEnergyCalculator::setEnergyType(
    EnergyType energyType
){
    this->energyType = energyType;
}*/

/*inline SelfEnergyCalculator::EnergyType SelfEnergyCalculator::getEnergyType(
) const{
    return energyType;
}*/

inline void SelfEnergyCalculator::setSelfEnergyEnergies(
    const std::vector<std::complex<double>> &selfEnergyEnergies
){
    this->selfEnergyEnergies = selfEnergyEnergies;
    selfEnergyTree.clear();
}

inline void SelfEnergyCalculator::setU(std::complex<double> U){
    this->U = U;

    for(
        unsigned int n = 0;
        n < electronFluctuationVertexCalculators.size();
        n++
    ){
        electronFluctuationVertexCalculators[n]->setU(U);
    }

    selfEnergyTree.clear();
}

inline void SelfEnergyCalculator::setUp(std::complex<double> Up){
    this->Up = Up;

    for(
        unsigned int n = 0;
        n < electronFluctuationVertexCalculators.size();
        n++
    ){
        electronFluctuationVertexCalculators[n]->setUp(Up);
    }

    selfEnergyTree.clear();
}

inline void SelfEnergyCalculator::setJ(std::complex<double> J){
    this->J = J;

    for(
        unsigned int n = 0;
        n < electronFluctuationVertexCalculators.size();
        n++
    ){
        electronFluctuationVertexCalculators[n]->setJ(J);
    }

    selfEnergyTree.clear();
}

inline void SelfEnergyCalculator::setJp(std::complex<double> Jp){
    this->Jp = Jp;

    for(
        unsigned int n = 0;
        n < electronFluctuationVertexCalculators.size();
        n++
    ){
        electronFluctuationVertexCalculators[n]->setJp(Jp);
    }

    selfEnergyTree.clear();
}

/*inline void SelfEnergyCalculator::precomputeSusceptibilities(
    unsigned int numWorkers
){
    susceptibilityCalculator.precompute(numWorkers);
}*/

inline void SelfEnergyCalculator::saveSusceptibilities(
    const std::string &filename
) const{
    size_t lastPos = filename.find_last_of('/');
    std::string path;
    std::string fname = filename;
    if(lastPos != std::string::npos){
        path = filename.substr(0, lastPos+1);
        fname = filename.substr(lastPos+1, filename.size());
    }

    for(
        unsigned int n = 0;
        n < electronFluctuationVertexCalculators.size();
        n++
    ){
        electronFluctuationVertexCalculators[n]->saveSusceptibilities(
                        path + "Slice" + std::to_string(n) + "_" + fname
        );
    }
}

inline void SelfEnergyCalculator::loadSusceptibilities(
    const std::string &filename
){
    size_t lastPos = filename.find_last_of('/');
    std::string path;
    std::string fname = filename;
    if(lastPos != std::string::npos){
        path = filename.substr(0, lastPos+1);
        fname = filename.substr(lastPos+1, filename.size());
    }

    for(
        unsigned int n = 0;
        n < electronFluctuationVertexCalculators.size();
        n++
    ){
        electronFluctuationVertexCalculators[n]->loadSusceptibilities(
                        path + "Slice" + std::to_string(n) + "_" + fname
        );
    }
}

};  //End of namespace TBTK

#endif