SpinResolved2DM.hpp

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// This file is part of GQCG-GQCP.
//
// Copyright (C) 2017-2020  the GQCG developers
//
// GQCG-GQCP is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GQCG-GQCP 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with GQCG-GQCP.  If not, see <http://www.gnu.org/licenses/>.
 
#pragma once
 
 
#include "Basis/Transformations/DoublySpinResolvedBasisTransformable.hpp"
#include "Basis/Transformations/DoublySpinResolvedJacobiRotatable.hpp"
#include "Basis/Transformations/UJacobiRotation.hpp"
#include "Basis/Transformations/UTransformation.hpp"
#include "DensityMatrix/MixedSpinResolved2DMComponent.hpp"
#include "DensityMatrix/Orbital2DM.hpp"
#include "DensityMatrix/PureSpinResolved2DMComponent.hpp"
#include "QuantumChemical/DoublySpinResolvedBase.hpp"
#include "QuantumChemical/Spin.hpp"
 
 
namespace GQCP {
 
 
template <typename _Scalar>
class SpinResolved2DM:
    public DoublySpinResolvedBase<PureSpinResolved2DMComponent<_Scalar>, MixedSpinResolved2DMComponent<_Scalar>, SpinResolved2DM<_Scalar>>,
    public DoublySpinResolvedBasisTransformable<SpinResolved2DM<_Scalar>>,
    public DoublySpinResolvedJacobiRotatable<SpinResolved2DM<_Scalar>> {
public:
    // The scalar type of one of the density matrix elements: real or complex.
    using Scalar = _Scalar;
 
    // The type of 'this'.
    using Self = SpinResolved2DM<Scalar>;
 
    // The type components this spin resolved object is made of.
    using PureComponentType = typename DoublySpinResolvedBase<PureSpinResolved2DMComponent<_Scalar>, MixedSpinResolved2DMComponent<_Scalar>, SpinResolved2DM<_Scalar>>::Pure;
    using MixedComponentType = typename DoublySpinResolvedBase<PureSpinResolved2DMComponent<_Scalar>, MixedSpinResolved2DMComponent<_Scalar>, SpinResolved2DM<_Scalar>>::Mixed;
 
 
public:
    /*
     *  MARK: Constructors
     */
 
    // Inherit `DoublySpinResolvedBase`'s constructors.
    using DoublySpinResolvedBase<PureSpinResolved2DMComponent<_Scalar>, MixedSpinResolved2DMComponent<_Scalar>, SpinResolved2DM<_Scalar>>::DoublySpinResolvedBase;
 
 
    /*
     *  MARK: General information
     */
 
    size_t numberOfOrbitals(const Spin sigma, const Spin tau) const {
 
        if (sigma == Spin::alpha && tau == Spin::beta) {
            return this->alphaAlpha().numberOfOrbitals();
        } else if (sigma == Spin::alpha && tau == Spin::beta) {
            return this->alphaBeta().numberOfOrbitals();
        } else if (sigma == Spin::beta && tau == Spin::alpha) {
            return this->betaAlpha().numberOfOrbitals();
        } else {
            return this->betaBeta().numberOfOrbitals();
        }
    }
 
 
    Orbital2DM<Scalar> orbitalDensity() const {
        return Orbital2DM<Scalar> {this->alphaAlpha().tensor().Eigen() + this->alphaBeta().tensor().Eigen() + this->betaAlpha().tensor().Eigen() + this->betaBeta().tensor().Eigen()};
    }
 
 
    // Since `rotate` and `rotated` are both defined in `DoublySpinResolvedBasisTransformable` and `DoublySpinResolvedJacobiRotatable`, we have to explicitly enable these methods here.
 
    // Allow the `rotate` method from `DoublySpinResolvedBasisTransformable`, since there's also a `rotate` from `DoublySpinResolvedJacobiRotatable`.
    using DoublySpinResolvedBasisTransformable<Self>::rotate;
 
    // Allow the `rotated` method from `DoublySpinResolvedBasisTransformable`, since there's also a `rotated` from `DoublySpinResolvedJacobiRotatable`.
    using DoublySpinResolvedBasisTransformable<Self>::rotated;
 
    // Allow the `rotate` method from `DoublySpinResolvedJacobiRotatable`, since there's also a `rotate` from `DoublySpinResolvedBasisTransformable`.
    using DoublySpinResolvedJacobiRotatable<Self>::rotate;
 
    // Allow the `rotated` method from `DoublySpinResolvedJacobiRotatable`, since there's also a `rotated` from `DoublySpinResolvedBasisTransformable`.
    using DoublySpinResolvedJacobiRotatable<Self>::rotated;
};
 
 
/*
 *  MARK: BasisTransformableTraits
 */
 
template <typename Scalar>
struct BasisTransformableTraits<SpinResolved2DM<Scalar>> {
 
    // The type of transformation that is naturally related to a `SpinResolved2DM`.
    using Transformation = UTransformation<Scalar>;
};
 
 
/*
 *  MARK: JacobiRotatableTraits
 */
 
template <typename Scalar>
struct JacobiRotatableTraits<SpinResolved2DM<Scalar>> {
 
    // The type of Jacobi rotation for which the Jacobi rotation should be defined.
    using JacobiRotationType = UJacobiRotation;
};
 
 
}  // namespace GQCP