/* permutation/init.c

 * 

 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough

 * 

 * This program 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 program; if not, write to the Free Software

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

 */

#include <config.h>

#include <stdlib.h>

#include <gsl/gsl_errno.h>

#include <gsl/gsl_permutation.h>

gsl_permutation *

gsl_permutation_alloc (const size_t n)

{

  gsl_permutation * p;

  if (n == 0)

    {

      GSL_ERROR_VAL ("permutation length n must be positive integer",

                        GSL_EDOM, 0);

    }

  p = (gsl_permutation *) malloc (sizeof (gsl_permutation));

  if (p == 0)

    {

      GSL_ERROR_VAL ("failed to allocate space for permutation struct",

                        GSL_ENOMEM, 0);

    }

  p->data = (size_t *) malloc (n * sizeof (size_t));

  if (p->data == 0)

    {

      free (p);         /* exception in constructor, avoid memory leak */

      GSL_ERROR_VAL ("failed to allocate space for permutation data",

                        GSL_ENOMEM, 0);

    }

  p->size = n;

  return p;

}

gsl_permutation *

gsl_permutation_calloc (const size_t n)

{

  size_t i;

  gsl_permutation * p =  gsl_permutation_alloc (n);

  if (p == 0)

    return 0;

  /* initialize permutation to identity */

  for (i = 0; i < n; i++)

    {

      p->data[i] = i;

    }

  return p;

}

void

gsl_permutation_init (gsl_permutation * p)

{

  const size_t n = p->size ;

  size_t i;

  /* initialize permutation to identity */

  for (i = 0; i < n; i++)

    {

      p->data[i] = i;

    }

}

void

gsl_permutation_free (gsl_permutation * p)

{

  RETURN_IF_NULL (p);

  free (p->data);

  free (p);

}