/* gsl_histogram_oper.c

 * Copyright (C) 2000  Simone Piccardi

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation; either version 3 of the

 * License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License along

 * with this library; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 */

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

 *

 * File gsl_histogram_oper.c: 

 * Routine to make operation on histograms. 

 * Need GSL library and header.

 * Contains the routines:

 * gsl_histogram_same_binning check if two histograms have the same binning 

 * gsl_histogram_add          add two histograms

 * gsl_histogram_sub          subctract two histograms

 * gsl_histogram_mult         multiply two histograms

 * gsl_histogram_div          divide two histograms

 * gsl_histogram_scale        scale histogram contents

 *

 * Author: S. Piccardi

 * Jan. 2000

 *

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

#include <config.h>

#include <stdlib.h>

#include <gsl/gsl_errno.h>

#include <gsl/gsl_histogram.h>

/* 

 * gsl_histogram_same_binning:

 * control if two histograms have the

 * same binning

 */

int

gsl_histogram_equal_bins_p (const gsl_histogram * h1, const gsl_histogram * h2)

{

  if (h1->n != h2->n)

    {

      return 0;

    }

  {

    size_t i;

    /* init ranges */

    for (i = 0; i <= h1->n; i++)

      {

        if (h1->range[i] != h2->range[i])

          {

            return 0;

          }

      }

  }

  return 1;

}

/* 

 * gsl_histogram_add:

 * add two histograms

 */

int 

gsl_histogram_add (gsl_histogram * h1, const gsl_histogram * h2)

{

  size_t i;

  if (!gsl_histogram_equal_bins_p (h1, h2))

    {

      GSL_ERROR ("histograms have different binning", GSL_EINVAL);

    }

  for (i = 0; i < h1->n; i++)

    {

      h1->bin[i] += h2->bin[i];

    }

  return GSL_SUCCESS;

}

/* 

 * gsl_histogram_sub:

 * subtract two histograms

 */

int 

gsl_histogram_sub (gsl_histogram * h1, const gsl_histogram * h2)

{

  size_t i;

  if (!gsl_histogram_equal_bins_p (h1, h2))

    {

      GSL_ERROR ("histograms have different binning", GSL_EINVAL);

    }

  for (i = 0; i < h1->n; i++)

    {

      h1->bin[i] -= h2->bin[i];

    }

  return GSL_SUCCESS;

}

/* 

 * gsl_histogram_mult:

 * multiply two histograms

 */

int 

gsl_histogram_mul (gsl_histogram * h1, const gsl_histogram * h2)

{

  size_t i;

  if (!gsl_histogram_equal_bins_p (h1, h2))

    {

      GSL_ERROR ("histograms have different binning", GSL_EINVAL);

    }

  for (i = 0; i < h1->n; i++)

    {

      h1->bin[i] *= h2->bin[i];

    }

  return GSL_SUCCESS;

}

/* 

 * gsl_histogram_div:

 * divide two histograms

 */

int 

gsl_histogram_div (gsl_histogram * h1, const gsl_histogram * h2)

{

  size_t i;

  if (!gsl_histogram_equal_bins_p (h1, h2))

    {

      GSL_ERROR ("histograms have different binning", GSL_EINVAL);

    }

  for (i = 0; i < h1->n; i++)

    {

      h1->bin[i] /= h2->bin[i];

    }

  return GSL_SUCCESS;

}

/* 

 * gsl_histogram_scale:

 * scale a histogram by a numeric factor

 */

int 

gsl_histogram_scale (gsl_histogram * h, double scale)

{

  size_t i;

  for (i = 0; i < h->n; i++)

    {

      h->bin[i] *= scale;

    }

  return GSL_SUCCESS;

}

/* 

 * gsl_histogram_shift:

 * shift a histogram by a numeric offset

 */

int 

gsl_histogram_shift (gsl_histogram * h, double shift)

{

  size_t i;

  for (i = 0; i < h->n; i++)

    {

      h->bin[i] += shift;

    }

  return GSL_SUCCESS;

}