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gnn_constant_input.c

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/***************************************************************************
 *  @file gnn_memory_input.c
 *  @brief Input Set Residing in Memory Implementation.
 *
 *  @date   : 22-09-03 01:21
 *  @author : Pedro Ortega C. <peortega@dcc.uchile.cl>
 *  Copyright  2003  Pedro Ortega C.
 ****************************************************************************/
/*
 *  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 2 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 Library 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */



/**
 * @defgroup gnn_constant_input_doc gnn_constant_input : Constant Input Samples.
 * @ingroup gnn_input_doc
 * @brief Constant Input samples.
 *
 * The \ref gnn_constant_input provides a single constant sample.
 */



/******************************************/
/* Include Files                          */
/******************************************/

#include "gnn_utilities.h"
#include "gnn_constant_input.h"



/******************************************/
/* Static Declaration                     */
/******************************************/

/**
 * @brief The datatype for the constant samples set.
 * @ingroup gnn_memory_input_doc
 *
 * This is the datatype for constant input sample set. It extends the basic
 * \ref gnn_input structure to include the additional pointer
 * to the sample vector.
 */
typedef struct _gnn_constant_input gnn_constant_input;

struct _gnn_constant_input
{
    gnn_input   set;    /**< The underlying \ref gnn_input */
    gsl_vector *vector; /**< The sample.                   */
};

static const gsl_vector *
gnn_constant_input_get (gnn_input *set, size_t k);

static void
gnn_constant_input_destroy (gnn_input *set);



/******************************************/
/* Static Implementation                  */
/******************************************/

/**
 * @brief The "get" function.
 * @ingroup gnn_constant_input_doc
 *
 * This function is returns the k-th pattern in the set.
 *
 * @param  set A pointer to a \ref gnn_constant.
 * @param  k   The index of the pattern to be retrieved.
 * @return A pointer to the sample vector.
 */
static const gsl_vector *
gnn_constant_input_get (gnn_input *set, size_t k)
{
    gnn_constant_input *cset;

    assert (set != NULL);

    /* get view as a constant sampler */
    cset = (gnn_constant_input *) set;

    return cset->vector;
}

/**
 * @brief Destroy function.
 * @ingroup gnn_constant_input_doc
 *
 * This is the \ref gnn_constant_input destroy function.
 * @param set A pointer to a \ref gnn_constant_input sampler.
 */
static void
gnn_constant_input_destroy (gnn_input *set)
{
    gnn_constant_input *cset;

    assert (set != NULL);
    
    cset = (gnn_constant_input *) set;
    
    if (cset->vector != NULL)
        gsl_vector_free (cset->vector);
}



/******************************************/
/* Public Interface                       */
/******************************************/

/**
 * @brief Builds an input set from a vector.
 * @ingroup gnn_constant_input_doc
 *
 * This function creates a new \ref gnn_constant_input from a vector.
 *
 * @param  v The sample vector.
 * @return Returns a pointer to a new \ref gnn_constant_input set.
 */
gnn_input *
gnn_constant_input_new_from_vector (const gsl_vector *v)
{
    int status;
    gnn_input *set;
    gnn_constant_input *cset;
    
    assert (v != NULL);
    
    /* create the set */
    set = gnn_constant_input_new (v->size, 0.0);
    if (set == NULL)
    {
        GSL_ERROR_VAL ("could not create gnn_constant_input",
                       GSL_EFAILED, NULL);
    }
    
    /* get view as a gnn_constant_input */
    cset = (gnn_constant_input *) set;
    
    /* copy vector values */
    gsl_vector_memcpy (cset->vector, v);
    
    return set;
}

/**
 * @brief Builds a input set with the given value.
 * @ingroup gnn_constant_input_doc
 *
 * This function creates a new \ref gnn_constant_input. The resulting
 * input sampler has a single sample vector of the given size. All its elements
 * have the same value.
 *
 * @param  n     The size of the sample.
 * @param  value The values for the sample's elements.
 * @return Returns a pointer to a new \ref gnn_constant_input set.
 */
gnn_input *
gnn_constant_input_new (size_t n, double value)
{
    int status;
    gnn_input *set;
    gnn_constant_input *cset;

    /* alloc memory for input set */
    cset = (gnn_constant_input *) malloc (sizeof (gnn_constant_input));

    /* get view as a input set */
    set = (gnn_input *) cset;

    /* initialize */
    status = gnn_input_init (set,
                             1,
                             n,
                             NULL,
                             gnn_constant_input_get,
                             gnn_constant_input_destroy);
    if (status)
    {
        gnn_input_destroy (set);
        GSL_ERROR_VAL ("could not initialize gnn_constant_input",
                       GSL_EINVAL, NULL);
    }

    /* create sample */
    cset->vector = gsl_vector_alloc (n);
    gsl_vector_set_all (cset->vector, value);

    return set;
}

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