/*
* 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.
*
*/
#pragma once
#ifndef XTP_VXC_POTENTIAL_H
#define XTP_VXC_POTENTIAL_H
#include <votca/xtp/grid_containers.h>
#include <votca/xtp/gridbox.h>
#include <xc.h>
#undef LOG
namespace votca {
namespace xtp {
template <class Grid>
class Vxc_Potential {
public:
explicit Vxc_Potential(const Grid& grid) : _grid(grid){};
~Vxc_Potential();
static double getExactExchange(const std::string& functional);
void setXCfunctional(const std::string& functional);
Mat_p_Energy IntegrateVXC(const Eigen::MatrixXd& density_matrix) const;
private:
struct XC_entry {
double f_xc = 0; // E_xc[n] = int{n(r)*eps_xc[n(r)] d3r} = int{ f_xc(r) d3r
double df_drho = 0; // v_xc_rho(r) = df/drho
double df_dsigma = 0; // df/dsigma ( df/dgrad(rho) = df/dsigma *
// dsigma/dgrad(rho) = df/dsigma * 2*grad(rho))
};
XC_entry EvaluateXC(double rho, double sigma) const;
const Grid _grid;
int xfunc_id;
bool _setXC = false;
bool _use_separate;
int cfunc_id;
xc_func_type xfunc; // handle for exchange functional
xc_func_type cfunc; // handle for correlation functional
};
} // namespace xtp
} // namespace votca
#endif // XTP_NUMERICAL_INTEGRATION_H