c_begin.c

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/*!
   \file cluster/c_begin.c
 
   \brief Cluster library - Begin clusterring
 
   (C) 2001-2009 by the GRASS Development Team
 
   This program is free software under the GNU General Public License
   (>=v2). Read the file COPYING that comes with GRASS for details.
 
   \author Original author CERL
 */
 
#include <stdlib.h>
#include <grass/glocale.h>
#include <grass/cluster.h>
 
/*!
   \brief Initialize the cluster routines for nbands
 
   \param C pointer to Cluster structure
   \param nbands number of bands
 
   \return 0 ok
   \return -1 out of memory
   \return 1 illegal number of bands
 */
int I_cluster_begin(struct Cluster *C, int nbands)
{
    int band;
 
    if (C->points != NULL) {
        for (band = 0; band < C->nbands; band++)
            if (C->points[band] != NULL)
                free(C->points[band]);
        free(C->points);
    }
    if (C->band_sum != NULL)
        free(C->band_sum);
    if (C->band_sum2 != NULL)
        free(C->band_sum2);
 
    C->points = NULL;
    C->band_sum = NULL;
    C->band_sum2 = NULL;
 
    I_free_signatures(&C->S);
 
    /* record the number of bands */
    C->nbands = nbands;
    if (nbands <= 0)
        return 1;
 
    /* prepare the signatures for nbands */
 
    I_init_signatures(&C->S, nbands);
    snprintf(C->S.title, sizeof(C->S.title), _("produced by i.cluster"));
 
    /* allocate the data (points) arrays */
    C->points = (DCELL **)malloc(C->nbands * sizeof(DCELL *));
    if (C->points == NULL)
        return -1;
    for (band = 0; band < C->nbands; band++)
        C->points[band] = NULL;
 
    C->np = 128;
    for (band = 0; band < C->nbands; band++) {
        C->points[band] = (DCELL *)malloc(C->np * sizeof(DCELL));
        if (C->points[band] == NULL)
            return -1;
    }
 
    /* initialize the count to zero */
    C->npoints = 0;
 
    /* allocate the band sums and means */
    C->band_sum = (double *)malloc(C->nbands * sizeof(double));
    if (C->band_sum == NULL)
        return -1;
    C->band_sum2 = (double *)malloc(C->nbands * sizeof(double));
    if (C->band_sum2 == NULL)
        return -1;
    for (band = 0; band < C->nbands; band++) {
        C->band_sum[band] = 0;
        C->band_sum2[band] = 0;
    }
 
    return 0;
}