src/gmxlib/maths.c

   1 /*
   2  * $Id$
   3  *
   4  *       This source code is part of
   5  *
   6  *        G   R   O   M   A   C   S
   7  *
   8  * GROningen MAchine for Chemical Simulations
   9  *
  10  *               VERSION 2.0
  11  *
  12  * Copyright (c) 1991-1999
  13  * BIOSON Research Institute, Dept. of Biophysical Chemistry
  14  * University of Groningen, The Netherlands
  15  *
  16  * Please refer to:
  17  * GROMACS: A message-passing parallel molecular dynamics implementation
  18  * H.J.C. Berendsen, D. van der Spoel and R. van Drunen
  19  * Comp. Phys. Comm. 91, 43-56 (1995)
  20  *
  21  * Also check out our WWW page:
  22  * http://md.chem.rug.nl/~gmx
  23  * or e-mail to:
  24  * gromacs@chem.rug.nl
  25  *
  26  * And Hey:
  27  * Green Red Orange Magenta Azure Cyan Skyblue
  28  */
  29 static char *SRCID_maths_c = "$Id$";
  30
  31 #include <math.h>
  32 #include "maths.h"
  33
  34 int gmx_nint(real a)
  35 {
  36   const real half = .5;
  37   int   result;
  38
  39   result = (a < 0.) ? ((int)(a - half)) : ((int)(a + half));
  40   return result;
  41 }
  42
  43 real sign(real x,real y)
  44 {
  45   if (y < 0)
  46     return -fabs(x);
  47   else
  48     return +fabs(x);
  49 }