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

/*!
  \file cluster/c_distinct.c
  
  \brief Cluster library - Distinct value
  
  (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 <grass/cluster.h>

/*!
  \brief Get distinct value

  \param C pointer to Cluster structure
  \param separation separation value

  \return distinction value
*/
int I_cluster_distinct(struct Cluster *C, double separation)
{
    int class1, class2;
    int distinct;
    double dmin;
    double dsep;

    /* compute sum of squares for each class */
    I_cluster_sum2(C);

    /* find closest classes */
    distinct = 1;
    dmin = separation;
    for (class1 = 0; class1 < (C->nclasses - 1); class1++) {
	if (C->count[class1] < 2)
	    continue;
	for (class2 = class1 + 1; class2 < C->nclasses; class2++) {
	    if (C->count[class2] < 2)
		continue;
	    dsep = I_cluster_separation(C, class1, class2);

	    if (dsep >= 0.0 && dsep < dmin) {
		distinct = 0;
		C->merge1 = class1;
		C->merge2 = class2;
		dmin = dsep;
	    }
	}
    }

    return distinct;
}