GRASS GIS 8 Programmer's Manual 8.3.2(2024)-exported
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dmaxe.c
Go to the documentation of this file.
1#include <stdio.h>
2#include <stdlib.h>
3#include <math.h>
4#include "local_proto.h"
5
6double *Cdhc_dmax_exp(double *x, int n)
7{
8 static double y[2];
9 double mean = 0.0, zmax, tmax, *xcopy, t, z, fx;
10 int i;
11
12 if ((xcopy = (double *)malloc(n * sizeof(double))) == NULL) {
13 fprintf(stderr, "Memory error in Cdhc_dmax_exp\n");
14 exit(EXIT_FAILURE);
15 }
16
17 for (i = 0; i < n; ++i) {
18 xcopy[i] = x[i];
19 mean += x[i];
20 }
21 mean /= n;
22
23 qsort(xcopy, n, sizeof(double), Cdhc_dcmp);
24
25 for (i = 0; i < n; ++i) {
26 fx = 1 - exp(-xcopy[i] / mean);
27 z = (double)(i + 1) / (double)n - fx;
28 t = fx - (double)i / (double)n;
29 if (i == 0 || z > zmax)
30 zmax = z;
31
32 if (i == 0 || t > tmax)
33 tmax = t;
34 }
35
36 y[0] = zmax;
37 y[1] = tmax;
38
39 free(xcopy);
40
41 return y;
42}
#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:6
double t
#define x