GreensFunction.h

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/* Copyright 2018 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_PROPERTY_GREENS_FUNCTION
#define COM_DAFER45_TBTK_PROPERTY_GREENS_FUNCTION

#include "TBTK/Property/EnergyResolvedProperty.h"
#include "TBTK/TBTKMacros.h"

#include <complex>
#include <vector>

namespace TBTK{
namespace Property{

class GreensFunction : public EnergyResolvedProperty<std::complex<double>>{
public:
    enum class Type{
        TimeOrdered,
        Advanced,
        Retarded,
        Principal,
        NonPrincipal,
        Matsubara
    };

    GreensFunction();

    GreensFunction(
        const IndexTree &indexTree,
        Type type,
        double lowerBound,
        double upperBound,
        unsigned int resolution
    );

    GreensFunction(
        const IndexTree &indexTree,
        Type type,
        double lowerBound,
        double upperBound,
        unsigned int resolution,
        const std::complex<double> *data
    );

    GreensFunction(
        const IndexTree &indexTree,
        int lowerMatsubaraEnergyIndex,
        int upperMatsubaraEnergyIndex,
        double fundamentalMatsubaraEnergy
    );

    GreensFunction(
        const IndexTree &indexTree,
        int lowerMatsubaraEnergyIndex,
        int upperMatsubaraEnergyIndex,
        double fundamentalMatsubaraEnergy,
        const std::complex<double> *data
    );

    GreensFunction& operator+=(const GreensFunction &rhs);

    GreensFunction operator+(const GreensFunction &rhs) const;

    GreensFunction& operator-=(const GreensFunction &rhs);

    GreensFunction operator-(const GreensFunction &rhs) const;

    GreensFunction& operator*=(const std::complex<double> &rhs);

    GreensFunction operator*(const std::complex<double> &rhs) const;

    friend GreensFunction operator*(
        const std::complex<double> &lhs,
        const GreensFunction &rhs
    ){
        return rhs*lhs;
    }

    GreensFunction& operator/=(const std::complex<double> &rhs);

    GreensFunction operator/(const std::complex<double> &rhs) const;

    Type getType() const;

    std::string toString() const;
private:
    Type type;
};

inline GreensFunction& GreensFunction::operator+=(const GreensFunction &rhs){
    TBTKAssert(
        type == rhs.type,
        "GreensFunction::operator+=()",
        "Incompatible Green's function types.",
        ""
    );

    EnergyResolvedProperty::operator+=(rhs);

    return *this;
}

inline GreensFunction GreensFunction::operator+(const GreensFunction &rhs) const{
    GreensFunction greensFunction = *this;

    return greensFunction += rhs;
}

inline GreensFunction& GreensFunction::operator-=(const GreensFunction &rhs){
    TBTKAssert(
        type == rhs.type,
        "GreensFunction::operator-=()",
        "Incompatible Green's function types.",
        ""
    );

    EnergyResolvedProperty::operator-=(rhs);

    return *this;
}

inline GreensFunction GreensFunction::operator-(const GreensFunction &rhs) const{
    GreensFunction greensFunction = *this;

    return greensFunction -= rhs;
}

inline GreensFunction& GreensFunction::operator*=(const std::complex<double> &rhs){
    EnergyResolvedProperty::operator*=(rhs);

    return *this;
}

inline GreensFunction GreensFunction::operator*(const std::complex<double> &rhs) const{
    GreensFunction greensFunction = *this;

    return greensFunction *= rhs;
}

inline GreensFunction& GreensFunction::operator/=(const std::complex<double> &rhs){
    EnergyResolvedProperty::operator/=(rhs);

    return *this;
}

inline GreensFunction GreensFunction::operator/(const std::complex<double> &rhs) const{
    GreensFunction greensFunction = *this;

    return greensFunction /= rhs;
}

inline GreensFunction::Type GreensFunction::getType() const{
    return type;
}

};  //End namespace Property
};  //End namespace TBTK

#endif