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

# include "ppc_array.h"
# include "ppc_image.h"
# include "ppc_image_analysis.h"
# include "ppc_xmalloc.h"

int main ( int argc, char **argv );
void clip_matrix_test ( );
void prune_pgm_test ( );
void timestamp ( );
void truncation_error_test ( );

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

int main ( int argc, char **argv )

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

    ppc_image_analysis() analyzes images.

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    23 April 2024

  Author:

    John Burkardt

  Reference:

    Rouben Rostamian,
    Programming Projects in C 
    for Students of Engineering, Science, and Mathematics,
    SIAM, 2014,
    ISBN: 978-1-611973-49-5
*/
{
  timestamp ( );
  printf ( "\n" );
  printf ( "ppc_image_analysis_test():\n" );
  printf ( "  C version\n" );
  printf ( "  Test ppc_image_analysis().\n" );

  clip_matrix_test ( );

  prune_pgm_test ( );

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

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

void clip_matrix_test ( )

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

    clip_matrix_test() tests clip_matrix().

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    17 September 2023

  Author:

    John Burkardt

  Reference:

    Rouben Rostamian,
    Programming Projects in C 
    for Students of Engineering, Science, and Mathematics,
    SIAM, 2014,
    ISBN: 978-1-611973-49-5
*/
{
  double **a;
  int i;
  int j;
  int M;
  int m;
  int n;

  printf ( "\n" );
  printf ( "clip_matrix_test():\n" );
  printf ( "  clip matrix() forces the entries of a matrix to be\n" );
  printf ( "  integers within a given range.\n" );

  m = 6;
  n = 5;
  M = 255;
  
  make_matrix ( a, m, n );

  for ( i = 0; i < m; i++ )
  {
    for ( j = 0; j < n; j++ )
    {
      a[i][j] = 255 * ( double ) rand ( ) / ( double ) ( RAND_MAX );
    }
  }

  printf ( "\n" );
  printf ( "  Random matrix:\n" );
  printf ( "\n" );
  print_matrix ( " %g", a, m, n );

  clip_matrix ( a, m, n, M );

  printf ( "\n" );
  printf ( "  After clipping:\n" );
  printf ( "\n" );
  print_matrix ( " %g", a, m, n );

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

void prune_pgm_test ( )

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

    prune_pgm_test() tests prune_pgm().

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    17 September 2023

  Author:

    John Burkardt

  Reference:

    Rouben Rostamian,
    Programming Projects in C 
    for Students of Engineering, Science, and Mathematics,
    SIAM, 2014,
    ISBN: 978-1-611973-49-5

  Input:

  Output:
*/
{
  double **a;
  int deleted;
  int i;
  int j;
  int m = 5;
  int n = 5;
  double norm_new;
  double norm_old;
  double ratio;
  double rel_err;

  printf ( "\n" );
  printf ( "prune_pgm_test():\n" );
  printf ( "  prune pgm() drops small matrix elements\n" );
  printf ( "  whose norm is less than some percentage of the matrix norm.\n" );

  make_matrix ( a, m, n );

  for ( i = 0; i < m; i++ )
  {
    for ( j = 0; j < n; j++ )
    {
      a[i][j] = ( double ) rand ( ) / ( double ) ( RAND_MAX );
    }
  }

  printf ( "\n" );
  printf ( "  Random matrix:\n" );
  printf ( "\n" );
  print_matrix ( " %g", a, m, n );

  norm_old = matrix_norm_frobenius ( a, m, n );
  printf ( "\n" );
  printf ( "  Matrix Frobenius norm: %g\n", norm_old );

  rel_err = 0.10;

  deleted = prune_pgm ( a, m, n, rel_err );

  printf ( "\n" );
  printf ( "  Pruned matrix:\n" );
  printf ( "\n" );
  print_matrix ( " %g", a, m, n );

  printf ( "  Number of elements deleted was %d\n", deleted );
  norm_new = matrix_norm_frobenius ( a, m, n );
  printf ( "\n" );
  printf ( "  Matrix Frobenius norm after pruning: %g\n", norm_new );
  ratio = fabs ( pow ( norm_new, 2 ) - pow ( norm_old, 2 ) ) / pow ( norm_old, 2 );
  printf ( "  Ratio norm_new - norm_old / norm_old = %g\n", ratio );

  free_matrix ( a );

  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
}
/******************************************************************************/

void truncation_error_test ( )

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

    truncation_error_test() tests truncation_error().

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    17 September 2023

  Author:

    John Burkardt

  Reference:

    Rouben Rostamian,
    Programming Projects in C 
    for Students of Engineering, Science, and Mathematics,
    SIAM, 2014,
    ISBN: 978-1-611973-49-5
*/
{
  double **a;
  double e;
  int i;
  int j;
  int m = 5;
  int n = 5;
  double t;

  printf ( "\n" );
  printf ( "truncation_error_test():\n" );
  printf ( "  truncation_error() measures error in neglecting matrix\n" );
  printf ( "  elements smaller than a given threshold.\n" );

  make_matrix ( a, m, n );

  t = 0.25;
  for ( i = 0; i < m; i++ )
  {
    for ( j = 0; j < n; j++ )
    {
      a[i][j] = ( double ) rand ( ) / ( double ) ( RAND_MAX );
    }
  }

  printf ( "\n" );
  printf ( "  Random matrix:\n" );
  printf ( "\n" );
  print_matrix ( " %g", a, m, n );

  printf ( "\n" );
  printf ( "  Threshold    Truncation error:\n" );
  printf ( "\n" );
  t = 1.0;
  for ( i = 0; i < 4; i++ )
  {
    t = t / 2.0;
    e = truncation_error ( t, a, m, n );
    printf ( "  For threshold t = %g, truncation error = %g\n", t, e );
  }

  free_matrix ( a );

  return;
}