GRASS GIS 8 Programmer's Manual 8.2.1(2023)-exported
c_exec.c
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1/*!
2 \file cluster/c_exec.c
3
4 \brief Cluster library - Exectute clusterring
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#include <grass/glocale.h>
16
17/*!
18 \param C pointer to Cluster structure
19 \param maxclass maximum number of classes
20 \param iterations maximum number of iterations
21 \param convergence percentage of points stable
22 \param separation minimum distance between class centroids
23 \param min_class_size minimum size of class
24 \param checkpoint routine to be called at various steps
25 \param interrupted boolean to check for interrupt
26
27 \return 0 ok
28 \return -1 out of memory
29 \return -2 interrupted
30 \return 1 not enough data points
31*/
32int I_cluster_exec(struct Cluster *C, int maxclass, int iterations,
33 double convergence,
34 double separation, int min_class_size,
35 int (*checkpoint) (), int *interrupted)
36{
37 int changes;
38
39 /* set interrupted to false */
40 *interrupted = 0;
41
42 /* check for valid inputs */
43 if (C->npoints < 2) {
44 G_warning(_("Not enough data points (%d) in cluster"), C->npoints);
45 return 1;
46 }
47
48 /* check other parms */
49 if (maxclass < 0)
50 maxclass = 1;
51 C->nclasses = maxclass;
52
53 if (min_class_size <= 0)
54 min_class_size = 17;
55 if (min_class_size < 2)
56 min_class_size = 2;
57
58 if (iterations <= 0)
59 iterations = 20;
60 if (convergence <= 0.0)
61 convergence = 98.0;
62 if (separation < 0.0)
63 separation = 0.5;
64
65
66 /* allocate memory */
68 return -1;
69
70
71 /* generate class means */
73 if (checkpoint)
74 (*checkpoint) (C, 1);
75
76 /* now assign points to nearest class */
77 I_cluster_assign(C, interrupted);
78 if (*interrupted)
79 return -2;
81 if (checkpoint)
82 (*checkpoint) (C, 2);
83
84 /* get rid of empty classes now */
86
87 for (C->iteration = 1;; C->iteration++) {
88 if (*interrupted)
89 return -2;
90
91 changes = 0;
92
93 /* re-assign points to nearest class */
94
95 changes = I_cluster_reassign(C, interrupted);
96 if (*interrupted)
97 return -2;
98
99 /* if too many points have changed class, re-assign points */
100 C->percent_stable = (C->npoints - changes) * 100.0;
101 C->percent_stable /= (double)C->npoints;
102
103 if (checkpoint)
104 (*checkpoint) (C, 3);
105
106 if (C->iteration >= iterations)
107 break;
108
109 if (C->percent_stable < convergence)
110 continue;
111
112 /* otherwise merge non-distinct classes */
113
114 if (I_cluster_distinct(C, separation))
115 break;
116
117 if (checkpoint)
118 (*checkpoint) (C, 4);
119
121 }
122
123 /* get rid of small classes */
124 I_cluster_reclass(C, min_class_size);
126
127 /* compute the resulting signatures */
129
130
131 return 0;
132}
int I_cluster_assign(struct Cluster *C, int *interrupted)
Assign cluster.
Definition: c_assign.c:26
int I_cluster_distinct(struct Cluster *C, double separation)
Get distinct value.
Definition: c_distinct.c:24
int I_cluster_exec(struct Cluster *C, int maxclass, int iterations, double convergence, double separation, int min_class_size, int(*checkpoint)(), int *interrupted)
Definition: c_exec.c:32
int I_cluster_exec_allocate(struct Cluster *C)
Allocate Cluster structure.
Definition: c_execmem.c:24
int I_cluster_means(struct Cluster *C)
Calculate means value.
Definition: c_means.c:24
int I_cluster_merge(struct Cluster *C)
?
Definition: c_merge.c:23
int I_cluster_reassign(struct Cluster *C, int *interrupted)
?
Definition: c_reassign.c:25
int I_cluster_reclass(struct Cluster *C, int minsize)
Reclass data.
Definition: c_reclass.c:25
int I_cluster_signatures(struct Cluster *C)
Create signatures.
Definition: c_sig.c:23
int I_cluster_sum2(struct Cluster *C)
Compute sum of squares for each class.
Definition: c_sum2.c:23
if(!DBFLoadRecord(psDBF, hEntity)) return NULL
void G_warning(const char *msg,...)
Print a warning message to stderr.
Definition: gis/error.c:204