bulk_properties.hpp

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// Copyright 2015-2018 The ALMA Project Developers
//
// 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.

#pragma once


#include <constants.hpp>
#include <structures.hpp>
#include <qpoint_grid.hpp>

namespace alma {
inline double calc_cv(const alma::Crystal_structure& poscar,
                      const alma::Gamma_grid& grid,
                      double T) {
    double nruter = 0.;
    double nqpoints = grid.nqpoints;
    double nmodes = grid.get_spectrum_at_q(0).omega.size();

    for (std::size_t iq = 0; iq < nqpoints; ++iq) {
        auto& spectrum = grid.get_spectrum_at_q(iq);

        for (std::size_t im = 0; im < nmodes; ++im)
            nruter += alma::bose_einstein_kernel(spectrum.omega(im), T);
    }
    nruter *= alma::constants::kB / nqpoints / poscar.V;
    return nruter;
}


Eigen::MatrixXd calc_kappa(const alma::Crystal_structure& poscar,
                           const alma::Gamma_grid& grid,
                           const Eigen::Ref<const Eigen::ArrayXXd>& w,
                           double T);

// free
Eigen::MatrixXd calc_kappa_sg(const alma::Crystal_structure& poscar,
                              const alma::Gamma_grid& grid,
                              double T);

double calc_kappa_1d(const alma::Crystal_structure& poscar,
                     const alma::Gamma_grid& grid,
                     const Eigen::Ref<const Eigen::ArrayXXd>& w,
                     double T,
                     const Eigen::Ref<const Eigen::Vector3d>& direction);
} // namespace alma