Geografic-Information-System/lib/cluster/c_assign.c

#include <math.h>
#include <grass/cluster.h>

int I_cluster_assign(struct Cluster *C, int *interrupted)
{
    int p, c;
    int class, band;
    double d, q;
    double dmin;

    /*
       fprintf (stderr,"I_cluster_assign(npoints=%d,nclasses=%d,nbands=%d)\n",
       C->npoints, C->nclasses, C->nbands);
     */

    for (p = 0; p < C->npoints; p++) {
	if (*interrupted)
	    return -1;

	dmin = HUGE_VAL;
	class = 0;
	for (c = 0; c < C->nclasses; c++) {
	    d = 0.0;
	    for (band = 0; band < C->nbands; band++) {
		q = C->points[band][p];
		q -= C->mean[band][c];
		d += q * q;
	    }
	    if (c == 0 || d < dmin) {
		class = c;
		dmin = d;
	    }
	}
	C->class[p] = class;
	C->count[class]++;
	for (band = 0; band < C->nbands; band++)
	    C->sum[band][class] += C->points[band][p];
    }

    return 0;
}