include/random.h

   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
  30 #ifndef _random_h
  31 #define _random_h
  32
  33 static char *SRCID_random_h = "$Id$";
  34
  35 #ifdef HAVE_IDENT
  36 #ident  "@(#) random.h 1.5 12/16/92"
  37 #endif /* HAVE_IDENT */
  38
  39 #include <typedefs.h>
  40
  41 extern real gauss(real am, real sd, int *ig);
  42 /* Generate a gaussian number with:
  43  * am = center of the distribution
  44  * sd = standard deviation
  45  * ig = the random number seed.
  46  */
  47
  48 extern int make_seed(void);
  49 /* Make a random seed: (time+getpid) % 65536 */
  50
  51 extern real rando(int *ig);
  52 /* Generate a random number 0 <= r < 1. ig is the (address of) the
  53  * seed variable.
  54  */
  55
  56 extern void grp_maxwell(t_block *grp,real tempi[],int nrdf[],int seed,
  57                         t_atoms *atoms,rvec v[]);
  58 /* Generate for each group in grp a temperature. */
  59
  60 extern void maxwell_speed(real tempi,int nrdf,int seed,
  61                           t_atoms *atoms, rvec v[]);
  62 /* Generate velocites according to a maxwellian distribution */
  63
  64 extern real calc_cm(FILE *log,int natoms,real mass[],rvec x[],rvec v[],
  65                     rvec xcm,rvec vcm,rvec acm,matrix L);
  66 /* Calculate the c.o.m. position, velocity, acceleration and the
  67  * moment of Inertia. Returns the total mass.
  68  */
  69
  70 extern void stop_cm(FILE *log,int natoms,real mass[],rvec x[],rvec v[]);
  71
  72 #endif  /* _random_h */