#include <config.h>
#include <math.h>
#include <gsl_histogram.h>
#include <gsl_test.h>

#include "urand.c"

int
main (void)
{
  size_t i;
  int status = 0;

  gsl_histogram *h = gsl_histogram_calloc_uniform (10, 0.0, 1.0);

  gsl_histogram_increment (h, 0.1);
  gsl_histogram_increment (h, 0.2);
  gsl_histogram_increment (h, 0.2);
  gsl_histogram_increment (h, 0.3);

  {
    gsl_histogram_pdf *p = gsl_histogram_pdf_alloc (h);

    gsl_histogram *hh = gsl_histogram_calloc_uniform (100, 0.0, 1.0);

    for (i = 0; i < 100000; i++)
      {
	double u = urand();
	double x = gsl_histogram_pdf_sample (p, u);
	gsl_histogram_increment (hh, x);
      }

    for (i = 0; i < 100; i++)
      {
	double y = gsl_histogram_get (hh, i) / 2500;
	double x, xmax;
	size_t k;
	double ya;

	gsl_histogram_get_range (hh, i, &x, &xmax);

	gsl_histogram_find (h, x, &k);
	ya = gsl_histogram_get (h, k);

	if (ya == 0)
	  {
	    if (y != 0)
	      {
		printf ("%d: %g vs %g\n", (int) i, y, ya);
		status = 1;
	      }
	  }
	else
	  {
	    double err = 1 / sqrt (gsl_histogram_get (hh, i));
	    double sigma = fabs ((y - ya) / (ya * err));
	    if (sigma > 3)
	      {
		status = 1;
		printf ("%g vs %g err=%g sigma=%g\n", y, ya, err, sigma);
	      }
	  }
      }

    gsl_histogram_pdf_free (p) ;
    gsl_histogram_free (hh);

    gsl_test (status, "gsl_histogram_pdf_sample within statistical errors");
  }

  gsl_histogram_free (h);

  return gsl_test_summary ();
}