# include <cmath>
# include <cstdlib>
# include <cstring>
# include <ctime>
# include <iomanip>
# include <iostream>

using namespace std;

# include "brownian_motion_simulation.hpp"

int main ( );
void timestamp ( );

//****************************************************************************80

int main ( )

//****************************************************************************80
//
//  Purpose:
//
//    brownian_motion_simulation_test() tests brownian_motion_simulation().
//
//  Licensing:
//
//    This code is distributed under the MIT license.
//
//  Modified:
//
//    11 February 2020
//
//  Author:
//
//    John Burkardt
//
{
  double d;
  double *dsq;
  string header;
  int k;
  int m;
  int n;
  int seed;
  double t;
  double *x;

  timestamp ( );
  cout << "\n";
  cout << "BROWNIAN_MOTION_SIMULATION_TEST():\n";
  cout << "  C++ version\n";
  cout << "  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 )
    {
      header = "motion_1d";
    }
    else if ( m == 2 )
    {
      header = "motion_2d";
    }
    brownian_motion_display ( m, n, x, header );
    delete [] 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 )
    {
      header = "displacement_1d";
    }
    else if ( m == 2 )
    {
      header = "displacement_2d";
    }
    else if ( m == 3 )
    {
      header = "displacement_3d";
    }
    brownian_displacement_display ( k, n, m, d, t, dsq, header );
    delete [] dsq;
  }
/*
  Terminate.
*/
  cout << "\n";
  cout << "BROWNIAN_MOTION_SIMULATION_TEST():\n";
  cout << "  Normal end of execution.\n";
  cout << "\n";
  timestamp ( );

  return 0;
}
//****************************************************************************80

void timestamp ( )

//****************************************************************************80
//
//  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:
//
//    08 July 2009
//
//  Author:
//
//    John Burkardt
//
{
# define TIME_SIZE 40

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

  now = std::time ( NULL );
  tm_ptr = std::localtime ( &now );

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

  std::cout << time_buffer << "\n";

  return;
# undef TIME_SIZE
}