GRASS GIS 7 Programmer's Manual  7.9.dev(2021)-e5379bbd7
c_sum2.c
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1 /*!
2  \file cluster/c_sum2.c
3
4  \brief Cluster library - Sum of squares
5
6  (C) 2001-2009 by the GRASS Development Team
7
8  This program is free software under the GNU General Public License
9  (>=v2). Read the file COPYING that comes with GRASS for details.
10
11  \author Original author CERL
12 */
13
14 #include <grass/cluster.h>
15
16 /*!
17  \brief Compute sum of squares for each class
18
19  \param C pointer to Cluster structure
20
21  \return 0
22 */
23 int I_cluster_sum2(struct Cluster *C)
24 {
25  int p, band, class;
26  double q;
27
28  G_debug(3, "I_cluster_sum2(npoints=%d,nclasses=%d,nbands=%d)",
29  C->npoints, C->nclasses, C->nbands);
30
31  for (class = 0; class < C->nclasses; class++)
32  for (band = 0; band < C->nbands; band++)
33  C->sum2[band][class] = 0;
34
35  for (p = 0; p < C->npoints; p++) {
36  class = C->class[p];
37  if (class < 0)
38  continue;
39  for (band = 0; band < C->nbands; band++) {
40  q = C->points[band][p];
41  C->sum2[band][class] += q * q;
42  }
43  }
44
45  return 0;
46 }
int nbands
Definition: cluster.h:9
int nclasses
Definition: cluster.h:27
Definition: cluster.h:7
int npoints
Definition: cluster.h:10
double ** sum2
Definition: cluster.h:23
DCELL ** points
Definition: cluster.h:11
int I_cluster_sum2(struct Cluster *C)
Compute sum of squares for each class.
Definition: c_sum2.c:23
int G_debug(int, const char *,...) __attribute__((format(printf