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

# include "closest_pair_brute.h"

int main ( );
double closest_pair_brute_test01 ( int n );
double cpu_time ( );
void timestamp ( );

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

int main ( )

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

    closest_pair_brute_test() tests closest_pair_brute().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    03 April 2024

  Author:

    John Burkardt
*/
{
  int i;
  int nvec[8] = 
    { 100, 200, 400, 800, 1600, 3200, 6400, 12800 };
  double svec[8];

  timestamp ( );
  printf ( "\n" );
  printf ( "closest_pair_brute_test()\n" );
  printf ( "  C version\n" );
  printf ( "  Test closest_pair_brute().\n" );
/*
  Solve a sequence of problems of increasing size N.
*/
  for ( i = 0; i < 8; i++ )
  {
    svec[i] = closest_pair_brute_test01 ( nvec[i] );
  }
/*
  Print the final table.
*/
  printf ( "\n" );
  printf ( "  Test  Points  Time\n" );
  printf ( "\n" );
  for ( i = 0; i < 8; i++ )
  {
    printf ( "  %4d  %6d  %14.6g\n", i, nvec[i], svec[i] );
  }
/*
  Terminate.
*/
  printf ( "\n" );
  printf ( "closest_pair_brute_test():\n" );
  printf ( "  Normal end of execution.\n" );
  printf ( "\n" );
  timestamp ( );

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

double closest_pair_brute_test01 ( int n )

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

    closest_pair_brute_test01() tests the closest_pair_brute program.

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    03 April 2024

  Author:

    John Burkardt

  Input:

    int n: the number of points.

  Output:

    double s: execution time in seconds.
*/
{
  double d;
  int i;
  int j;
  double s;
  long int seed;
  double *xy;

  printf ( "\n" );
  printf ( "closest_pair_brute_test01():\n" );
  printf ( "  closest_pair_brute() on a set of N points in 2D.\n" );

  xy = ( double * ) malloc ( n * 2 * sizeof ( double ) );

  seed = 123456789L;
  srand48 ( seed );

  for ( j = 0; i <= 1; j++ )
  {
    for ( i = 0; i <= n; i++ )
    {
      xy[i+j*n] = drand48 ( );
    }
  }

  s = cpu_time ( );
  closest_pair_brute ( n, xy, &d, &i, &j );
  s = cpu_time ( ) - s;

  printf ( "\n" );
  printf ( "  n = %d\n", n );
  printf ( "  time in seconds = %g\n", s );
  printf ( "  xy(%d) = (%g,%g)\n", i, xy[i+0*n], xy[i+1*n] );
  printf ( "  xy(%d) = (%g,%g)\n", j, xy[j+0*n], xy[j+1*n] );
  printf ( "  distance = %g\n", d );

  free ( xy );

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

double cpu_time ( )

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

    cpu_time() returns the current reading on the CPU clock.

  Discussion:

    The CPU time measurements available through this routine are often
    not very accurate.  In some cases, the accuracy is no better than
    a hundredth of a second.  

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    06 June 2005

  Author:

    John Burkardt

  Output:

    double cpu_time(): the current reading of the CPU clock, in seconds.
*/
{
  double value;

  value = ( double ) clock ( ) 
        / ( double ) CLOCKS_PER_SEC;

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

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
}