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

# include "test_interp_1d.h"
# include "pwl_approx_1d.h"
# include "r8lib.h"

int main ( );
void test01 ( int prob, int nc, int nd );

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

int main ( )

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

    MAIN is the main program for PWL_APPROX_1D_TEST.

  Discussion:

    PWL_APPROX_1D_TEST tests the PWL_APPROX_1D library.

  Licensing:

    This code is distributed under the GNU LGPL license.

  Modified:

    09 October 2012

  Author:

    John Burkardt
*/
{
  int j;
  int k;
  int nc;
  int nc_test[4] = { 2, 4, 8, 16 };
  int nc_test_num = 4;
  int nd;
  int nd_test[2] = { 16, 64 };
  int nd_test_num = 2;
  int prob;
  int prob_num;

  timestamp ( );
  printf ( "\n" );
  printf ( "PWL_APPROX_1D_TEST:\n" );
  printf ( "  C version\n" );
  printf ( "  Test the PWL_APPROX_1D library.\n" );
  printf ( "  The QR_SOLVE library is needed.\n" );
  printf ( "  The R8LIB library is needed.\n" );
  printf ( "  The test also needs the TEST_INTERP_1D library.\n" );

  prob_num = p00_prob_num ( );

  for ( prob = 1; prob <= prob_num; prob++ )
  {
    for ( j = 0; j < nc_test_num; j++ )
    {
      nc = nc_test[j];
      for ( k = 0; k < nd_test_num; k++ )
      {
        nd = nd_test[k];
        test01 ( prob, nc, nd );
      }
    }
  }
/*
  Terminate.
*/
  printf ( "\n" );
  printf ( "PWL_APPROX_1D_TEST:\n" );
  printf ( "  Normal end of execution.\n" );
  printf ( "\n" );
  timestamp ( );

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

void test01 ( int prob, int nc, int nd )

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

    TEST01 tests PWL_APPROX_1D.

  Licensing:

    This code is distributed under the GNU LGPL license.

  Modified:

    09 October 2012

  Author:

    John Burkardt

  Parameters:

    Input, int PROB, the problem index.

    Input, int NC, the number of control points.

    Input, int ND, the number of data points.
*/
{
  double app_error;
  int ni;
  double *xc;
  double *xd;
  double *xi;
  double *yc;
  double *yd;
  double *yi;
  double xmax;
  double xmin;

  printf ( "\n" );
  printf ( "TEST01:\n" );
  printf ( "  Approximate data from TEST_INTERP_1D problem #%d\n", prob );
  printf ( "  Number of control points = %d\n", nc );
  printf ( "  Number of data points = %d\n", nd );

  xmin = 0.0;
  xmax = 1.0;

  xd = r8vec_linspace_new ( nd, xmin, xmax );
  yd = p00_f ( prob, nd, xd );

  if ( nd < 10 )
  {
    r8vec2_print ( nd, xd, yd, "  Data array:" );
  }
/*
  Determine control values.
*/ 
  xc = r8vec_linspace_new ( nc, xmin, xmax );
  yc = pwl_approx_1d ( nd, xd, yd, nc, xc );
/*
  #1:  Does approximant come close to function at data points?
*/
  ni = nd;
  xi = r8vec_copy_new ( ni, xd );
  yi = pwl_interp_1d ( nc, xc, yc, ni, xi );

  app_error = r8vec_norm_affine ( ni, yi, yd ) / ( double ) ( ni );

  printf ( "\n" );
  printf ( "  L2 approximation error averaged per data node = %g\n", app_error );

  free ( xc );
  free ( xd );
  free ( xi );
  free ( yc );
  free ( yd );
  free ( yi );

  return;
}