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

# include "test_lls.h"
# include "r8lib.h"

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

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

int main ( )

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

    test_lls_test() tests test_lls().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    07 September 2012

  Author:

    John Burkardt
*/
{
  timestamp ( );
  printf ( "\n" );
  printf ( "TEST_LLS_TEST\n" );
  printf ( "  C version\n" );
  printf ( "  Test the TEST_LLS library.\n" );
  printf ( "  This test also requires the R8LIB library.\n" );

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

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

void test01 ( )

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

    TEST01 summarizes the test data.

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    07 September 2012

  Author:

    John Burkardt
*/
{
  double *a;
  double *b;
  double b_norm;
  int i;
  int j;
  int m;
  int n;
  int prob;
  int prob_num;
  double *r;
  double r_norm;
  double *x;
  double x_norm;

  printf ( "\n" );
  printf ( "TEST01\n" );
  printf ( "  Get each least squares test and compute the maximum residual.\n" );
  printf ( "  The L2 norm of the residual MUST be no greater than\n" );
  printf ( "  the L2 norm of the right hand side, else 0 is a better solution.\n" );

  prob_num = p00_prob_num ( );

  printf ( "\n" );
  printf ( "  Number of problems = %d\n", prob_num );
  printf ( "\n" );
  printf ( "  Index     M     N     ||B||         ||X||         ||R||\n" );
  printf ( "\n" );

  for ( prob = 1; prob <= prob_num; prob++ )
  {
    m = p00_m ( prob );
    n = p00_n ( prob );

    a = p00_a ( prob, m, n );
    b = p00_b ( prob, m );
    x = p00_x ( prob, n );

    r = ( double * ) malloc ( m * sizeof ( double ) );

    for ( i = 0; i < m; i++ )
    {
      r[i] = - b[i];
      for ( j = 0; j < n; j++ )
      {
        r[i] = r[i] + a[i+j*m] * x[j];
      }
    }

    b_norm = r8vec_norm ( m, b );
    x_norm = r8vec_norm ( n, x );
    r_norm = r8vec_norm ( m, r );

    printf ( "  %5d  %4d  %4d  %12g  %12g  %12g\n", 
      prob, m, n, b_norm, x_norm, r_norm );

    free ( a );
    free ( b );
    free ( r );
    free ( x );
  }
  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
}