/*
* Copyright 2009-2019 The VOTCA Development Team
* (http://www.votca.org)
*
* 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 _VOTCA_XTP_SIGMA_EXACT_H
#define _VOTCA_XTP_SIGMA_EXACT_H
#include <votca/xtp/rpa.h>
#include <votca/xtp/sigma_base.h>
namespace votca {
namespace xtp {
class TCMatrix_gwbse;
class RPA;
class Sigma_Exact : public Sigma_base {
public:
Sigma_Exact(TCMatrix_gwbse& Mmn, RPA& rpa) : Sigma_base(Mmn, rpa){};
// Sets up the screening parametrisation
void PrepareScreening() final;
// Calculates Sigma_c diagonal elements
double CalcCorrelationDiagElement(Index gw_level,
double frequency) const final;
double CalcCorrelationDiagElementDerivative(Index gw_level,
double frequency) const final;
// Calculates Sigma_c off-diagonal elements
double CalcCorrelationOffDiagElement(Index gw_level1, Index gw_level2,
double frequency1,
double frequency2) const final;
private:
RPA::rpa_eigensolution _rpa_solution; // Eigenvalues, eigenvectors from RPA
std::vector<Eigen::MatrixXd> _residues; // Residues
Eigen::MatrixXd CalcResidues(Index gw_level) const;
};
} // namespace xtp
} // namespace votca
#endif /* _VOTCA_XTP_SIGMA_EXACT_H */