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

# include "biharmonic_exact.h"

int main ( );
void timestamp ( );

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

int main ( )

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

    biharmonic_exact_test() tests biharmonic_exact().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    02 August 2024

  Author:

    John Burkardt
*/
{
  double a;
  double b;
  double c;
  double d;
  double e;
  double f;
  double g;
  int i;
  int n = 5;
  double r;
  double x;
  double y;

  timestamp ( );
  printf ( "\n" );
  printf ( "biharmonic_exact_test():\n" );
  printf ( "  C version\n" );
  printf ( "  Test biharmonic_exact().\n" );

  a = 1.0;
  b = 2.0;
  c = 3.0;
  d = 4.0;
  e = 5.0;
  f = 6.0;
  g = 7.0;
/*
  Exact function 1.
*/
  printf ( "\n" );
  printf ( "  Exact solution 1 residual at random points:\n" );

  for ( i = 0; i < n; i++ )
  {
    x = drand48 ( );
    y = drand48 ( );
    r = biharmonic_exact_r1 ( x, y, a, b, c, d, e, f, g );
    printf ( "  %2d  %10.4f  %10.4f  %14.6g\n", i, x, y, r );
  }
/*
  Exact function 2.
*/
  printf ( "\n" );
  printf ( "  Exact solution 2 residual at random points:\n" );

  for ( i = 0; i < n; i++ )
  {
    x = drand48 ( );
    y = drand48 ( );
    r = biharmonic_exact_r2 ( x, y, a, b, c, d, e, f, g );
    printf ( "  %2d  %10.4f  %10.4f  %14.6g\n", i, x, y, r );
  }
/*
  Exact function 3.
*/
  printf ( "\n" );
  printf ( "  Exact solution 3 residual at random points:\n" );

  for ( i = 0; i < n; i++ )
  {
    x = drand48 ( );
    y = drand48 ( );
    r = biharmonic_exact_r3 ( x, y, a, b, c, d, e, f );
    printf ( "  %2d  %10.4f  %10.4f  %14.6g\n", i, x, y, r );
  }
/*
  Terminate.
*/
  printf ( "\n" );
  printf ( "biharmonic_exact_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
*/
{
# 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
}