/*-------------- Telecommunications & Signal Processing Lab ---------------
                             McGill University

Routine:
  double MSfGaussRand (double rms)

Purpose:
  Generate a Gaussian pseudo-random value

Description:
  This routine generates pseudo-random numbers with a Gaussian distribution.
  The numbers are generated by summing 12 uniformly distributed pseudo-random
  numbers.  The result is approximately Gaussian (central limit theorem) with a
  range between -6 and +6 standard deviations.  This routine uses the function
  UTfUnifRand as the source of uniform pseudo-random numbers.

Parameters:
  <-  double MSfGaussRand
      Gaussian deviate, mean zero, standard deviation rms
   -> double rms
      Root-mean square value of the deviate (standard deviation)

Author / revision:
  P. Kabal  Copyright (C) 1996
  $Revision: 1.5 $  $Date: 1996/04/17 19:45:35 $

-------------------------------------------------------------------------*/

static char rcsid[] = "$Id: MSfGaussRand.c 1.5 1996/04/17 AFsp-V2R1 $";

#include <libtsp.h>

double
MSfGaussRand (rms)

     double rms;

{
  int i;
  double sum;

/* Add twelve uniform deviates, each in the range (0,1) */
   sum = 0.0;
   for (i = 0; i < 12; ++i)
     sum += MSfUnifRand ();

  return (rms * (sum - 6.0));
}