2 * This file is part of the GROMACS molecular simulation package.
4 * Copyright (c) 1991-2000, University of Groningen, The Netherlands.
5 * Copyright (c) 2001-2004, The GROMACS development team.
6 * Copyright (c) 2010,2014,2019,2021, by the GROMACS development team, led by
7 * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
8 * and including many others, as listed in the AUTHORS file in the
9 * top-level source directory and at http://www.gromacs.org.
11 * GROMACS is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public License
13 * as published by the Free Software Foundation; either version 2.1
14 * of the License, or (at your option) any later version.
16 * GROMACS is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with GROMACS; if not, see
23 * http://www.gnu.org/licenses, or write to the Free Software Foundation,
24 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
26 * If you want to redistribute modifications to GROMACS, please
27 * consider that scientific software is very special. Version
28 * control is crucial - bugs must be traceable. We will be happy to
29 * consider code for inclusion in the official distribution, but
30 * derived work must not be called official GROMACS. Details are found
31 * in the README & COPYING files - if they are missing, get the
32 * official version at http://www.gromacs.org.
34 * To help us fund GROMACS development, we humbly ask that you cite
35 * the research papers on the package. Check out http://www.gromacs.org.
37 #ifndef GMX_PBCUTIL_ISHIFT_H
38 #define GMX_PBCUTIL_ISHIFT_H
42 //! Maximum dimensions of grid expressing shifts across PBC
44 constexpr int c_dBoxZ = 1;
45 constexpr int c_dBoxY = 1;
46 constexpr int c_dBoxX = 2;
50 constexpr int c_nBoxZ = 2 * gmx::c_dBoxZ + 1;
51 constexpr int c_nBoxY = 2 * gmx::c_dBoxY + 1;
52 constexpr int c_nBoxX = 2 * gmx::c_dBoxX + 1;
53 constexpr int c_numIvecs = detail::c_nBoxZ * detail::c_nBoxY * detail::c_nBoxX;
56 constexpr int c_centralShiftIndex = detail::c_numIvecs / 2;
57 constexpr int c_numShiftVectors = detail::c_numIvecs;
59 //! Convert grid coordinates to shift index
60 static inline int xyzToShiftIndex(int x, int y, int z)
62 return (detail::c_nBoxX * (detail::c_nBoxY * ((z) + gmx::c_dBoxZ) + (y) + gmx::c_dBoxY) + (x)
66 //! Convert grid coordinates to shift index
67 static inline int ivecToShiftIndex(ivec iv)
69 return (xyzToShiftIndex((iv)[XX], (iv)[YY], (iv)[ZZ]));
72 //! Return the shift in the X dimension of grid space corresponding to \c iv
73 static inline int shiftIndexToXDim(int iv)
75 return (((iv) % detail::c_nBoxX) - gmx::c_dBoxX);