GRASS GIS 8 Programmer's Manual 8.4.1(2025)-45ca3179ab
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dmax.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_dmax(double *x, int n)
7{
8 static double y[2];
9 double *xcopy, sqrt2, mean = 0.0, sdx = 0.0, fx;
10 double dp, dp_max, dm, dm_max;
11 int i;
12
13 if ((xcopy = (double *)malloc(n * sizeof(double))) == NULL) {
14 fprintf(stderr, "Memory error in Cdhc_dmax\n");
15 exit(EXIT_FAILURE);
16 }
17
18 sqrt2 = sqrt((double)2.0);
19
20 for (i = 0; i < n; ++i) {
21 xcopy[i] = x[i];
22 mean += x[i];
23 sdx += x[i] * x[i];
24 }
25 sdx = sqrt((n * sdx - mean * mean) / (n * (n - 1.0)));
26 mean /= n;
27
28 qsort(xcopy, n, sizeof(double), Cdhc_dcmp);
29
30 for (i = 0; i < n; ++i) {
31 xcopy[i] = (xcopy[i] - mean) / sdx;
32 fx = 0.5 + Cdhc_normp(xcopy[i] / sqrt2) / 2.0;
33 if (fx <= 1e-5)
34 fx = 1e-5;
35
36 if (fx >= 0.99999)
37 fx = 0.99999;
38
39 dp = (double)(i + 1) / (double)n - fx;
40 dm = fx - i / (double)n;
41 if (i == 0 || dp > dp_max)
42 dp_max = dp;
43
44 if (i == 0 || dm > dm_max)
45 dm_max = dm;
46 }
47
48 y[0] = dp_max;
49 y[1] = dm_max;
50
51 free(xcopy);
52
53 return y;
54}
#define NULL
Definition ccmath.h:32
int Cdhc_dcmp(const void *i, const void *j)
Definition dcmp.c:1
double * Cdhc_dmax(double *x, int n)
Definition dmax.c:6
double Cdhc_normp(double z)
Definition normp.c:22
#define x