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

# include "tetrahedron01_monte_carlo.h"

int main ( );
void test01 ( );
void timestamp ( );

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

int main ( )

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

    tetrahedron01_monte_carlo_test() tests tetrahedron01_monte_carlo().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    16 January 2014

  Author:

    John Burkardt
*/
{
  timestamp ( );
  printf ( "\n" );
  printf ( "TETRAHEDRON01_MONTE_CARLO_TEST():\n" );
  printf ( "  C version\n" );
  printf ( "  Test TETRAHEDRON01_MONTE_CARLO().\n" );

  test01 ( );
/*
  Terminate.
*/
  printf ( "\n" );
  printf ( "TETRAHEDRON01_MONTE_CARLO_TEST():\n" );
  printf ( "  Normal end of execution.\n" );
  printf ( "\n" );
  timestamp ( );

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

void test01 ( )

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

    TEST01 uses TETRAHEDRON01_SAMPLE with an increasing number of points.

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    15 January 2014

  Author:

    John Burkardt
*/
{
  int e[3];
  int e_test[3*10] = {
    0, 0, 0, 
    1, 0, 0, 
    0, 1, 0, 
    0, 0, 1, 
    2, 0, 0, 
    1, 1, 0, 
    1, 0, 1, 
    0, 2, 0, 
    0, 1, 1, 
    0, 0, 2 };
  int i;
  int j;
  int m = 3;
  int n;
  double result;
  int seed;
  double *value;
  double *x;

  printf ( "\n" );
  printf ( "TEST01\n" );
  printf ( "  Use TETRAHEDRON01_SAMPLE for a Monte Carlo estimate of an\n" );
  printf ( "  integral over the interior of the unit tetrahedron in 3D.\n" );

  seed = 123456789;

  printf ( "\n" );
  printf ( "         N        1               X               Y " );
  printf ( "              Z               X^2              XY             XZ" );
  printf ( "              Y^2             YZ               Z^2\n" );
  printf ( "\n" );

  n = 1;

  while ( n <= 65536 )
  {
    x = tetrahedron01_sample ( n, &seed );
    printf ( "  %8d", n );

    for ( j = 0; j < 10; j++ )
    {
      for ( i = 0; i < m; i++ )
      {
        e[i] = e_test[i+j*m];
      }
      value = monomial_value ( m, n, e, x );

      result = tetrahedron01_volume ( ) * r8vec_sum ( n, value ) 
        / ( double ) ( n );
      printf ( "  %14.6g", result );

      free ( value );
    }

    printf ( "\n" );

    free ( x );

    n = 2 * n;
  }

  printf ( "\n" );
  printf ( "     Exact" );
  for ( j = 0; j < 10; j++ )
  {
    for ( i = 0; i < m; i++ )
    {
      e[i] = e_test[i+j*m];
    }
    result = tetrahedron01_monomial_integral ( e );
    printf ( "  %14.6g", result );
  }

  printf ( "\n" );

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

void timestamp ( )

/******************************************************************************/
/*
  Purpose:
 
    timestamp() prints the current YMDHMS date as a time stamp.

  Example:

    17 June 2014 09:45:54 AM

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    01 May 2021

  Author:

    John Burkardt
*/
{
# 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 );

  printf ( "%s\n", time_buffer );

  return;
# undef TIME_SIZE
}