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SPACE.H

Go to the documentation of this file.

#ifndef CH_SPACE_H
#define CH_SPACE_H

#ifdef CH_LANG_CC
/* _______              __
  / ___/ /  ___  __ _  / /  ___
 / /__/ _ \/ _ \/  ' \/ _ \/ _ \
 \___/_//_/\___/_/_/_/_.__/\___/ 
*/
//
// This software is copyright (C) by the Lawrence Berkeley
// National Laboratory.  Permission is granted to reproduce
// this software for non-commercial purposes provided that
// this notice is left intact.
// 
// It is acknowledged that the U.S. Government has rights to
// this software under Contract DE-AC03-765F00098 between
// the U.S.  Department of Energy and the University of
// California.
//
// This software is provided as a professional and academic
// contribution for joint exchange. Thus it is experimental,
// is provided ``as is'', with no warranties of any kind
// whatsoever, no support, no promise of updates, or printed
// documentation. By using this software, you acknowledge
// that the Lawrence Berkeley National Laboratory and
// Regents of the University of California shall have no
// liability with respect to the infringement of other
// copyrights by any part of this software.
//

//
// $Id: SPACE.H,v 1.3 2001/06/20 02:56:58 ligocki Exp $
//
#endif

#if ! defined(CH_SPACEDIM)
#error CH_SPACEDIM must be defined
#endif

#if (CH_SPACEDIM != 1 && CH_SPACEDIM !=2 && CH_SPACEDIM != 3)
#error CH_SPACEDIM must be either 1, 2, or 3
#endif

#if !defined(CH_LANG_FORT) || defined(CH_LANG_CC)

/*@ManDoc:
  The SpaceDim C++ integer constant specifies the dimension of the
  Chombo library to be built.  It is initialized to the value of
  the macro CH\_SPACEDIM.  Hence it will have one of the values 1, 2, or 3.

  C++ code that depends on the dimensionality of the problem that
  you're trying to solve should be cast in terms of this constant,
  instead of the CH\_SPACEDIM macro, if possible, as constants are
  visible to debuggers while macros are not.
*/
   const int SpaceDim = CH_SPACEDIM;
#endif

#if CH_SPACEDIM==1

/*@ManDoc:
  The D\_EXPR(a,b,c) macro expands to a comma expression that will
  evaluate SpaceDim of its arguments, counting from the left; i.e.
  CH\_SPACEDIM==1 implies only `a' is evaluated, CH\_SPACEDIM==2
  implies both `a' and `b', and CH\_SPACEDIM==3 implies all three
  arguments are evaluated.  This macro can be used to enhance
  the portability of code that works with structures whose size
  depends on CH\_SPACEDIM.
           
  For example:

     D\_EXPR(vect[0] *= s, vect[1] *= s, vect[2] *= s);

  More explicitly, this macro evaluates to one of

     ((void)((a),0))

     ((void)((a),(b),0))

     ((void)((a),(b),(c),0))

  corresponding to CH\_SPACEDIM values of 1, 2, or 3.
*/
#  define D_EXPR(a,b,c) ((void)((a),0))

/*@ManDoc:
  The D\_DECL(a,b,c) macro expands to a comma-separated list of
  1, 2, or all 3 of the arguments of the call, depending on the
  value of CH\_SPACEDIM.  This can be used to write portable
  function calls that depend on 1, 2, or 3 arguments, corresponding
  to the value of CH\_SPACEDIM.

  For example:

     return IntVect(D\_DECL(p[0] + s, p[1] + s, p[2] + s));

  More explicitly, this macro evaluates to one of

     a

     a,b

     a,b,c

  corresponding to CH\_SPACEDIM values of 1, 2, or 3.
*/
#  define D_DECL(a,b,c) a

/*@ManDoc:
  The D\_TERM(a,b,c) macro expands to a whitespace-separated list of
  1, 2, or all 3 of the arguments of the call, depending on the value
  of CH\_SPACEDIM.  This can be used to write program logic
  that depend on 1, 2, or 3 arguments, corresponding to
  the value of CH\_SPACEDIM.

  For example:

     return D\_TERM(len[0], *len[1], *len[2]);

  More explicitly, this macro evaluates to one of

     a

     a b

     a b c

  corresponding to CH\_SPACEDIM values of 1, 2, or 3.
*/
#  define D_TERM(a,b,c) a
#elif CH_SPACEDIM==2
#  define D_EXPR(a,b,c) ((void)((a),(b),0))
#  define D_DECL(a,b,c) a,b
#  define D_TERM(a,b,c) a b
#elif CH_SPACEDIM==3
#  define D_EXPR(a,b,c) ((void)((a),(b),(c),0))
#  define D_DECL(a,b,c) a,b,c
#  define D_TERM(a,b,c) a b c
#endif

#endif /*CH_SPACE_H*/

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