GRASS GIS 8 Programmer's Manual 8.2.1(2023)-exported
basic.c
Go to the documentation of this file.
1#include <math.h>
2#include <grass/arraystats.h>
3
4
5/*provides basic univar stats */
6void AS_basic_stats(double *data, int count, struct GASTATS *stats)
7{
8 int i = 1;
9 double sum = 0, sumsq = 0, sumabs = 0;
10 double dev = 0, dev2 = 0;
11
12 stats->count = count;
13 stats->min = data[0];
14 stats->max = data[count - 1];
15
16 for (i = 0; i < count; i++) {
17 sum += data[i];
18 sumabs += fabs(data[i]);
19 sumsq += data[i] * data[i];
20 }
21 stats->sum = sum;
22 stats->sumabs = sumabs;
23 stats->sumsq = sumsq;
24
25 stats->mean = stats->sum / stats->count;
26 stats->meanabs = stats->sumabs / stats->count;
27 for (i = 0; i < count; i++) {
28 dev2 = dev2 + (data[i] - stats->mean) * (data[i] - stats->mean);
29 dev = dev + (data[i] - stats->mean);
30 }
31
32
33 stats->var = (dev2 - (dev * dev / stats->count)) / stats->count;
34 stats->stdev = sqrt(stats->var);
35
36 return;
37}
38
39
40void AS_eqdrt(double vectx[], double vecty[], int i1, int i2, double *vabc)
41{
42 double bn = 0, bd = 0, x1 = 0, y1 = 0;
43
44 vabc[0] = 0;
45 vabc[1] = 0;
46 vabc[2] = 0;
47 if (i1 == 0) {
48 x1 = 0;
49 y1 = 0;
50 }
51 else {
52 x1 = vectx[i1];
53 y1 = vecty[i1];
54 }
55 bn = y1 - vecty[i2];
56 bd = x1 - vectx[i2];
57 if (bd != 0) {
58 vabc[1] = bn / bd;
59 vabc[0] = y1 - vabc[1] * x1;
60 return;
61 }
62 if (bn != 0)
63 vabc[2] = x1;
64 else
65 G_debug(3, "Points are equal\n");
66 return;
67}
void AS_eqdrt(double vectx[], double vecty[], int i1, int i2, double *vabc)
Definition: basic.c:40
void AS_basic_stats(double *data, int count, struct GASTATS *stats)
Definition: basic.c:6
int G_debug(int level, const char *msg,...)
Print debugging message.
Definition: debug.c:65
int count