/*
 * $Id: ishift.h,v 1.9 2003/11/17 21:50:44 spoel Exp $
 * 
 *                This source code is part of
 * 
 *                 G   R   O   M   A   C   S
 * 
 *          GROningen MAchine for Chemical Simulations
 * 
 *                        VERSION 3.2.0
 * Written by David van der Spoel, Erik Lindahl, Berk Hess, and others.
 * Copyright (c) 1991-2000, University of Groningen, The Netherlands.
 * Copyright (c) 2001-2004, The GROMACS development team,
 * check out http://www.gromacs.org for more information.

 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * If you want to redistribute modifications, please consider that
 * scientific software is very special. Version control is crucial -
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 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#define D_BOX_Z 1
#ifdef ALLOW_OFFDIAG_LT_HALFDIAG
#define D_BOX_Y 2
#define D_BOX_X 2
#else
#define D_BOX_Y 1
#define D_BOX_X 1
#endif 
#define N_BOX_Z (2*D_BOX_Z+1)
#define N_BOX_Y (2*D_BOX_Y+1)
#define N_BOX_X (2*D_BOX_X+1)
#define N_IVEC  (N_BOX_Z*N_BOX_Y*N_BOX_X)
#define CENTRAL (N_IVEC/2)
#define SHIFTS  N_IVEC

#define XYZ2IS(x,y,z) (N_BOX_X*(N_BOX_Y*((z)+D_BOX_Z)+(y)+D_BOX_Y)+(x)+D_BOX_X)
#define IVEC2IS(iv)   (XYZ2IS((iv)[XX],(iv)[YY],(iv)[ZZ]))
#define IS2X(iv)      (((iv) % N_BOX_X) - D_BOX_X)
#define IS2Y(iv)      ((((iv) / N_BOX_X) % N_BOX_Y) - D_BOX_Y)
#define IS2Z(iv)      ((iv) / (N_BOX_X*N_BOX_Y) - D_BOX_Z)
