/* multimin/fminimizer.c

 * 

 * Copyright (C) 2002, 2009 Tuomo Keskitalo, Ivo Alxneit

 * 

 * 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 <gsl/gsl_errno.h>

#include <gsl/gsl_multimin.h>

gsl_multimin_fminimizer *

gsl_multimin_fminimizer_alloc (const gsl_multimin_fminimizer_type * T,

                               size_t n)

{

  int status;

  gsl_multimin_fminimizer *s =

    (gsl_multimin_fminimizer *) malloc (sizeof (gsl_multimin_fminimizer));

  if (s == 0)

    {

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

                     GSL_ENOMEM, 0);

    }

  s->type = T;

  s->x = gsl_vector_calloc (n);

  if (s->x == 0) 

    {

      free (s);

      GSL_ERROR_VAL ("failed to allocate space for x", GSL_ENOMEM, 0);

    }

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

  if (s->state == 0)

    {

      gsl_vector_free (s->x);

      free (s);

      GSL_ERROR_VAL ("failed to allocate space for minimizer state",

                     GSL_ENOMEM, 0);

    }

  status = (T->alloc) (s->state, n);

  if (status != GSL_SUCCESS)

    {

      free (s->state);

      gsl_vector_free (s->x);

      free (s);

      GSL_ERROR_VAL ("failed to initialize minimizer state", GSL_ENOMEM, 0);

    }

  return s;

}

int

gsl_multimin_fminimizer_set (gsl_multimin_fminimizer * s,

                             gsl_multimin_function * f,

                             const gsl_vector * x,

                             const gsl_vector * step_size)

{

  if (s->x->size != f->n)

    {

      GSL_ERROR ("function incompatible with solver size", GSL_EBADLEN);

    }

  if (x->size != f->n || step_size->size != f->n) 

    {

      GSL_ERROR ("vector length not compatible with function", GSL_EBADLEN);

    }  

  s->f = f;

  gsl_vector_memcpy (s->x,x);

  return (s->type->set) (s->state, s->f, s->x, &(s->size), step_size);

}

void

gsl_multimin_fminimizer_free (gsl_multimin_fminimizer * s)

{

  RETURN_IF_NULL (s);

  (s->type->free) (s->state);

  free (s->state);

  gsl_vector_free (s->x);

  free (s);

}

int

gsl_multimin_fminimizer_iterate (gsl_multimin_fminimizer * s)

{

  return (s->type->iterate) (s->state, s->f, s->x, &(s->size), &(s->fval));

}

const char * 

gsl_multimin_fminimizer_name (const gsl_multimin_fminimizer * s)

{

  return s->type->name;

}

gsl_vector * 

gsl_multimin_fminimizer_x (const gsl_multimin_fminimizer * s)

{

  return s->x;

}

double 

gsl_multimin_fminimizer_minimum (const gsl_multimin_fminimizer * s)

{

  return s->fval;

}

double

gsl_multimin_fminimizer_size (const gsl_multimin_fminimizer * s)

{

  return s->size;

}