/*
* 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 VOTCA_XTP_FOURCENTER_H
#define VOTCA_XTP_FOURCENTER_H
#include <votca/xtp/eigen.h>
/**
* \brief Calculates four center electron overlap integrals for DFT.
*
*
*
*/
namespace votca {
namespace xtp {
class AOBasis;
class AOShell;
class FCMatrix {
public:
void Fill_4c_small_molecule(const AOBasis& dftbasis);
const Eigen::VectorXd& get_4c_vector() const { return _4c_vector; }
bool FillFourCenterRepBlock(Eigen::Tensor<double, 4>& block,
const AOShell& shell_1, const AOShell& shell_2,
const AOShell& shell_3,
const AOShell& shell_4) const;
private:
Eigen::VectorXd _4c_vector;
};
} // namespace xtp
} // namespace votca
#endif // VOTCA_XTP_FOURCENTER_H