# include <stdlib.h>
# include <stdio.h>
# include <math.h>
# include <string.h>
# include <time.h>

# include "brownian_motion_simulation.h"

int main ( );
void timestamp ( );

/******************************************************************************/

int main ( )

/******************************************************************************/
/*
  Purpose:

    brownian_motion_simulation_test() tests brownian_motion_simulation().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    01 October 2012

  Author:

    John Burkardt
*/
{
  double d;
  double *dsq;
  char header[80];
  int k;
  int m;
  int n;
  int seed;
  double t;
  double *x;

  timestamp ( );
  printf ( "\n" );
  printf ( "BROWNIAN_MOTION_SIMULATION_TEST():\n" );
  printf ( "  C version\n" );
  printf ( "  Test BROWNIAN_MOTION_SIMULATION().\n" );
/*
  Compute the path of a particle undergoing Brownian motion.
*/
  for ( m = 1; m <= 2; m++ )
  {
    n = 1001;
    d = 10.0;
    t = 1.0;
    seed = 123456789;
    x = brownian_motion_simulation ( m, n, d, t, &seed );
    if ( m == 1 )
    {
      strcpy ( header, "motion_1d" );
    }
    else if ( m == 2 )
    {
      strcpy ( header, "motion_2d" );
    }
    brownian_motion_display ( m, n, x, header );
    free ( x );
  }
/*
  Estimate the average displacement of the particle from the origin
  as a function of time.
*/
  for ( m = 1; m <= 3; m++ )
  {
    k = 40;
    n = 1001;
    d = 10.0;
    t = 1.0;
    seed = 123456789;

    dsq = brownian_displacement_simulation ( k, n, m, d, t, &seed );
    if ( m == 1 )
    {
      strcpy ( header, "displacement_1d" );
    }
    else if ( m == 2 )
    {
      strcpy ( header, "displacement_2d" );
    }
    else if ( m == 3 )
    {
      strcpy ( header, "displacement_3d" );
    }
    brownian_displacement_display ( k, n, m, d, t, dsq, header );
    free ( dsq );
  }
/*
  Terminate.
*/
  printf ( "\n" );
  printf ( "BROWNIAN_MOTION_SIMULATION_TEST():\n" );
  printf ( "  Normal end of execution.\n" );
  printf ( "\n" );
  timestamp ( );

  return 0;
}
/******************************************************************************/

void timestamp ( )

/******************************************************************************/
/*
  Purpose:

    TIMESTAMP prints the current YMDHMS date as a time stamp.

  Example:

    31 May 2001 09:45:54 AM

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    24 September 2003

  Author:

    John Burkardt

  Parameters:

    None
*/
{
# define TIME_SIZE 40

  static char time_buffer[TIME_SIZE];
  const struct tm *tm;
  time_t now;

  now = time ( NULL );
  tm = localtime ( &now );

  strftime ( time_buffer, TIME_SIZE, "%d %B %Y %I:%M:%S %p", tm );

  fprintf ( stdout, "%s\n", time_buffer );

  return;
# undef TIME_SIZE
}