GRASS GIS 8 Programmer's Manual 8.2.1RC1(2022)-exported
watsonun.c
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1#include <stdio.h>
2#include <stdlib.h>
3#include <math.h>
4#include "local_proto.h"
5
6
7double *Cdhc_watson_u2(double *x, int n)
8{
9 double *xcopy, mean = 0.0, sdx = 0.0, sqrt2, zbar = 0.0;
10 double fn2, fx, sum4 = 0.0;
11 static double y[2];
12 int i;
13
14 sqrt2 = sqrt((double)2.0);
15
16 if ((xcopy = (double *)malloc(n * sizeof(double))) == NULL) {
17 fprintf(stderr, "Memory error in Cdhc_anderson_darling\n");
18 exit(EXIT_FAILURE);
19 }
20
21 for (i = 0; i < n; ++i) {
22 xcopy[i] = x[i];
23 mean += x[i];
24 sdx += x[i] * x[i];
25 }
26 sdx = sqrt((n * sdx - mean * mean) / (n * (n - 1)));
27 mean /= n;
28
29 qsort(xcopy, n, sizeof(double), Cdhc_dcmp);
30
31 for (i = 0; i < n; ++i) {
32 xcopy[i] = (xcopy[i] - mean) / sdx;
33 fn2 = (2.0 * (i + 1) - 1.0) / (2.0 * n);
34 fx = 0.5 + Cdhc_normp(xcopy[i] / sqrt2) / 2.0;
35
36 if (fx <= 0.0)
37 fx = 1e-5;
38
39 if (fx >= 1.0)
40 fx = 0.99999;
41
42 zbar += fx;
43 sum4 += (fx - fn2) * (fx - fn2);
44 }
45
46 zbar /= n;
47 y[0] = (1.0 / (n * 12) + sum4) - n * (zbar - .5) * (zbar - .5);
48 y[0] *= 0.5 / n + 1.0;
49
50#ifdef NOISY
51 fprintf(stdout, " TEST6 WU2(N) =%10.4f\n", y[0]);
52#endif /* NOISY */
53
54 free(xcopy);
55
56 return y;
57}
#define NULL
Definition: ccmath.h:32
int Cdhc_dcmp(const void *i, const void *j)
Definition: dcmp.c:1
double Cdhc_normp(double z)
Definition: normp.c:23
double * Cdhc_watson_u2(double *x, int n)
Definition: watsonun.c:7
#define x