GRASS GIS 8 Programmer's Manual 8.4.1(2025)-45ca3179ab
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chisqn.c
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1#include <stdio.h>
2#include <stdlib.h>
3#include <math.h>
4#include "local_proto.h"
5
6double *Cdhc_chi_square(double *x, int n)
7{
8 static double y[2];
9 double mean = 0.0, sdx = 0.0, sum3 = 0.0, *v;
10 int i, j, k, *f;
11
12 k = rint(4.0 * pow(0.75 * (n - 1.0) * (n - 1.0), 0.2));
13
14 while ((double)(n / k) < 5.0)
15 --k;
16
17 if ((f = (int *)calloc(k, sizeof(int))) == NULL) {
18 fprintf(stderr, "Memory error in Cdhc_chi_square\n");
19 exit(EXIT_FAILURE);
20 }
21 if ((v = (double *)malloc((k + 1) * sizeof(double))) == NULL) {
22 fprintf(stderr, "Memory error in Cdhc_chi_square\n");
23 exit(EXIT_FAILURE);
24 }
25
26 for (i = 0; i < n; ++i) {
27 mean += x[i];
28 sdx += x[i] * x[i];
29 }
30 sdx = sqrt((n * sdx - mean * mean) / (n * (n - 1.0)));
31 mean /= n;
32
33 v[0] = -1e9;
34 for (i = 1; i < k; ++i)
35 v[i] = mean + Cdhc_xinormal((double)i / k) * sdx;
36
37 v[k] = 1e9;
38
39 for (i = 0; i < n; ++i) {
40 j = 0;
41 while (j < k) {
42 if (x[i] > v[j] && x[i] <= v[j + 1]) {
43 f[j]++;
44 j = k;
45 }
46 j++;
47 }
48 }
49
50 for (i = 0; i < k; ++i)
51 sum3 += f[i] * f[i];
52
53 y[0] = sum3 * k / n - n;
54 y[1] = (double)k - 3.0;
55
56#ifdef NOISY
57 fprintf(stdout, " TEST12 CS(N) =%10.4f DOF =%10.4f\n", y[0], y[1]);
58#endif /* NOISY */
59
60 free(f);
61 free(v);
62
63 return y;
64}
#define NULL
Definition ccmath.h:32
double * Cdhc_chi_square(double *x, int n)
Definition chisqn.c:6
#define x
double Cdhc_xinormal(double pee)
Definition xinormal.c:4