Orbital2DM.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/RTransformation.hpp"
#include "DensityMatrix/DensityMatrixTraits.hpp"
#include "DensityMatrix/Orbital1DM.hpp"
#include "DensityMatrix/Simple2DM.hpp"
 
 
namespace GQCP {
 
 
/*
 *  MARK: `Orbital2DM` implementation
 */
 
template <typename _Scalar>
class Orbital2DM:
    public Simple2DM<_Scalar, Orbital2DM<_Scalar>> {
public:
    // The scalar type used for a density matrix element: real or complex.
    using Scalar = _Scalar;
 
public:
    /*
     *  MARK: Constructors
     */
 
    // Inherit `Simple2DM`'s constructors.
    using Simple2DM<Scalar, Orbital2DM<Scalar>>::Simple2DM;
};
 
 
/*
 *  MARK: `DensityMatrixTraits`
 */
 
template <typename Scalar>
struct DensityMatrixTraits<Orbital2DM<Scalar>> {
 
    // The type of transformation that is naturally related to an `Orbital2DM`. The only transformations that should be naturally possible for an orbital 2-DM are restricted transformations, thereby assuming that the density matrices for alpha-alpha, alpha-beta, beta-alpha and beta-beta are equal and thus transform similarly.
    using Transformation = RTransformation<Scalar>;
 
    // The type of the one-electron density matrix that is naturally related to an `Orbital2DM`.
    using OneDM = Orbital1DM<Scalar>;
};
 
 
/*
 *  MARK: `BasisTransformableTraits`
 */
 
template <typename Scalar>
struct BasisTransformableTraits<Orbital2DM<Scalar>> {
 
    // The type of transformation that is naturally related to an `Orbital2DM`. The only transformations that should be naturally possible for an orbital 2-DM are restricted transformations, thereby assuming that the density matrices for alpha-alpha, alpha-beta, beta-alpha and beta-beta are equal and thus transform similarly.
    using Transformation = RTransformation<Scalar>;
};
 
 
/*
 *  MARK: `JacobiRotatableTraits`
 */
 
template <typename Scalar>
struct JacobiRotatableTraits<Orbital2DM<Scalar>> {
 
    // The type of Jacobi rotation that is naturally related to a `G2DM`.
    using JacobiRotationType = JacobiRotation;
};
 
 
}  // namespace GQCP