/*
* 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_VC2INDEX_H
#define _VOTCA_XTP_VC2INDEX_H
#include <votca/tools/types.h>
namespace votca {
namespace xtp {
/**
* \brief This class transforms a pair of indices v,c into a compound index I,
* via I=ctotal*v+c the fast dimension is c. If you have a choice iterate over c
* and v not over I.
*
*
*/
class vc2index {
public:
vc2index(Index vmin, Index cmin, Index ctotal)
: _vmin(vmin), _cmin(cmin), _ctotal(ctotal){};
inline Index I(Index v, Index c) const {
return _ctotal * (v - _vmin) + (c - _cmin);
}
inline Index v(Index index) const { return (index / _ctotal + _vmin); }
inline Index c(Index index) const { return (index % _ctotal + _cmin); }
private:
Index _vmin;
Index _cmin;
Index _ctotal;
};
} // namespace xtp
} // namespace votca
#endif /* _VOTCA_XTP_VC2INDEX_H */