/* roots/fsolver.c

 * 

 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Reid Priedhorsky, 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 <string.h>

#include <gsl/gsl_errno.h>

#include <gsl/gsl_roots.h>

gsl_root_fsolver *

gsl_root_fsolver_alloc (const gsl_root_fsolver_type * T)

{

  gsl_root_fsolver * s = (gsl_root_fsolver *) malloc (sizeof (gsl_root_fsolver));

  if (s == 0)

    {

      GSL_ERROR_VAL ("failed to allocate space for root solver struct",

                        GSL_ENOMEM, 0);

    };

  s->state = malloc (T->size);

  if (s->state == 0)

    {

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

      GSL_ERROR_VAL ("failed to allocate space for root solver state",

                        GSL_ENOMEM, 0);

    };

  s->type = T ;

  s->function = NULL ;

  return s;

}

int

gsl_root_fsolver_set (gsl_root_fsolver * s, gsl_function * f, double x_lower, double x_upper)

{

  if (x_lower > x_upper)

    {

      GSL_ERROR ("invalid interval (lower > upper)", GSL_EINVAL);

    }

  s->function = f;

  s->root = 0.5 * (x_lower + x_upper);  /* initial estimate */

  s->x_lower = x_lower;

  s->x_upper = x_upper;

  return (s->type->set) (s->state, s->function, &(s->root), x_lower, x_upper);

}

int

gsl_root_fsolver_iterate (gsl_root_fsolver * s)

{

  return (s->type->iterate) (s->state, 

                             s->function, &(s->root), 

                             &(s->x_lower), &(s->x_upper));

}

void

gsl_root_fsolver_free (gsl_root_fsolver * s)

{

  RETURN_IF_NULL (s);

  free (s->state);

  free (s);

}

const char *

gsl_root_fsolver_name (const gsl_root_fsolver * s)

{

  return s->type->name;

}

double

gsl_root_fsolver_root (const gsl_root_fsolver * s)

{

  return s->root;

}

double

gsl_root_fsolver_x_lower (const gsl_root_fsolver * s)

{

  return s->x_lower;

}

double

gsl_root_fsolver_x_upper (const gsl_root_fsolver * s)

{

  return s->x_upper;

}