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

# include "test_eigen.h"

int main ( );
void r8nsymm_gen_test ( );
void r8symm_gen_test ( );
void timestamp ( );

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

int main ( )

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

    test_eigen_test() tests test_eigen().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    09 March 2018

  Author:

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

  r8symm_gen_test ( );
  r8nsymm_gen_test ( );
/*
  Terminate.
*/
  printf ( "\n" );
  printf ( "test_eigen_test():\n" );
  printf ( "  Normal end of execution.\n" );
  printf ( "\n" );
  timestamp ( );

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

void r8symm_gen_test ( )

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

    r8symm_gen_test() tests r8symm_gen().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    05 June 2024

  Author:

    John Burkardt
*/
{
  double *A;
  double *aq;
  int i;
  int j;
  double *lambda;
  double *lambda2;
  double lambda_dev = 5.0;
  double lambda_mean = 10.0;
  int n = 5;
  double *Q;
  int seed = 123456789;

  printf ( "\n" );
  printf ( "r8symm_gen_test():\n" );
  printf ( "  r8symm_gen() generates an arbitrary size symmetric matrix\n" );
  printf ( "  with known eigenvalues and eigenvectors.\n" );

  A = ( double * ) malloc ( n * n * sizeof ( double ) );
  Q = ( double * ) malloc ( n * n * sizeof ( double ) );
  lambda = ( double * ) malloc ( n * sizeof ( double ) );

  r8symm_gen ( n, lambda_mean, lambda_dev, &seed, A, Q, lambda );

  r8mat_print ( n, n, A, "  The matrix A:" );
  r8mat_print ( n, n, Q, "  The eigenvector matrix Q:" );
  r8vec_print ( n, lambda, "  The eigenvalue vector LAMBDA:" );

  aq = r8mat_mm_new ( n, n, n, A, Q );

  lambda2 = ( double * ) malloc ( n * sizeof ( double ) );

  for ( j = 0; j < n; j++ )
  {
    lambda2[j] = 0.0;
    for ( i = 0; i < n; i++ )
    {
      lambda2[j] = lambda2[j] + pow ( aq[i+j*n], 2 );
    }
    lambda2[j] = sqrt ( lambda2[j] );
  }

  r8vec2_print ( n, lambda, lambda2, "  LAMBDA versus the column norms of A*Q:" );
/*
  Free memory.
*/
  free ( A );
  free ( aq );
  free ( lambda );
  free ( lambda2 );
  free ( Q );

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

void r8nsymm_gen_test ( )

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

    r8nsymm_gen_test() tests r8nsymm_gen().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    04 June 2024

  Author:

    John Burkardt
*/
{
  double *A;
  int i;
  double *lambda;
  double lambda_dev = 5.0;
  double lambda_mean = 10.0;
  int n = 5;
  double *Q;
  int seed = 123456789;
  double *T;

  printf ( "\n" );
  printf ( "r8nsymm_gen_test():\n" );
  printf ( "  r8nsymm_gen() generates an arbitrary size nonsymmetric matrix\n" );
  printf ( "  with known eigenvalues and eigenvectors.\n" );

  A = ( double * ) malloc ( n * n * sizeof ( double ) );
  Q = ( double * ) malloc ( n * n * sizeof ( double ) );
  T = ( double * ) malloc ( n * n * sizeof ( double ) );

  r8nsymm_gen ( n, lambda_mean, lambda_dev, &seed, A, Q, T );

  lambda = ( double * ) malloc ( n * sizeof ( double ) );

  for ( i = 0; i < n; i++ )
  {
    lambda[i] = T[i+i*n];
  }
  r8vec_sort_bubble_a ( n, lambda );

  r8mat_print ( n, n, A, "  The matrix A:" );
  r8mat_print ( n, n, Q, "  The orthogonal factor Q:" );
  r8mat_print ( n, n, T, "  The upper triangular T:" );
  r8vec_print ( n, lambda, "  The eigenvalue vector LAMBDA:" );
/*
  Free memory.
*/
  free ( A );
  free ( lambda );
  free ( Q );
  free ( T );

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

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
}