GRASS GIS 7 Programmer's Manual  7.7.svn(2018)-r73566
cvmw2n.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
6
7 double *Cdhc_cramer_von_mises(double *x, int n)
8 {
9  int i;
10  static double y[2];
11  double mean = 0.0, sdx = 0.0, fx, sqrt2, *xcopy;
12
13  sqrt2 = sqrt((double)2.0);
14  y[1] = 0.0;
15
16  if ((xcopy = (double *)malloc(n * sizeof(double))) == NULL) {
17  fprintf(stderr, "Memory error in Cdhc_cramer_von_mises\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 - 1.0)));
27  mean /= n;
28
29  qsort(xcopy, n, sizeof(double), Cdhc_dcmp);
30
31  for (i = 0; i < n; ++i) {
32  fx = 0.5 + Cdhc_normp((xcopy[i] - mean) / sdx / sqrt2) / 2.0;
33  if (fx <= 1e-5)
34  fx = 1e-5;
35
36  if (fx >= 0.99999)
37  fx = 0.99999;
38
39  fx -= (2.0 * i + 1.0) / (2.0 * n);
40  y[1] += fx * fx;
41  }
42  y[1] += 1.0 / (double)(n * 12);
43  y[0] = y[1] * (0.5 / n + 1.0);
44
45 #ifdef NOISY
46  fprintf(stdout, " TEST9 CVM(N) =%10.4f\n", y[0]);
47 #endif /* NOISY */
48
49  free(xcopy);
50
51  return y;
52 }
void free(void *)
#define NULL
Definition: ccmath.h:32
#define x
void * malloc(YYSIZE_T)
double * Cdhc_cramer_von_mises(double *x, int n)
Definition: cvmw2n.c:7
int Cdhc_dcmp(const void *i, const void *j)
Definition: dcmp.c:1
float mean(IClass_statistics *statistics, int band)
Helper function for computing mean.
double Cdhc_normp(double z)
Definition: normp.c:23