GRASS GIS 8 Programmer's Manual 8.2.0(2022)-exported
dmaxe.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_dmax_exp(double *x, int n)
8{
9 static double y[2];
10 double mean = 0.0, zmax, tmax, *xcopy, t, z, fx;
11 int i;
12
13 if ((xcopy = (double *)malloc(n * sizeof(double))) == NULL) {
14 fprintf(stderr, "Memory error in Cdhc_dmax_exp\n");
15 exit(EXIT_FAILURE);
16 }
17
18 for (i = 0; i < n; ++i) {
19 xcopy[i] = x[i];
20 mean += x[i];
21 }
22 mean /= n;
23
24 qsort(xcopy, n, sizeof(double), Cdhc_dcmp);
25
26 for (i = 0; i < n; ++i) {
27 fx = 1 - exp(-xcopy[i] / mean);
28 z = (double)(i + 1) / (double)n - fx;
29 t = fx - (double)i / (double)n;
30 if (i == 0 || z > zmax)
31 zmax = z;
32
33 if (i == 0 || t > tmax)
34 tmax = t;
35 }
36
37 y[0] = zmax;
38 y[1] = tmax;
39
40 free(xcopy);
41
42 return y;
43}
#define NULL
Definition: ccmath.h:32
int Cdhc_dcmp(const void *i, const void *j)
Definition: dcmp.c:1
double * Cdhc_dmax_exp(double *x, int n)
Definition: dmaxe.c:7
double t
#define x