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watsonue.c
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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "local_proto.h"
double *Cdhc_watson_u2_exp(double *x, int n)
{
double *xcopy, mean = 0.0, zbar = 0.0, fn2, fx, sum4 = 0.0;
static double y[2];
int i;
if ((xcopy = (double *)malloc(n * sizeof(double))) == NULL) {
fprintf(stderr, "Memory error in Cdhc_watson_u2_exp\n");
exit(EXIT_FAILURE);
}
for (i = 0; i < n; ++i) {
xcopy[i] = x[i];
mean += x[i];
}
mean /= n;
qsort(xcopy, n, sizeof(double), Cdhc_dcmp);
for (i = 0; i < n; ++i) {
fx = 1 - exp(-xcopy[i] / mean);
if (fx <= 1e-5)
fx = 1e-5;
if (fx >= 0.99999)
fx = 0.99999;
/* sum3 += 2 * (i + 1) * (log (fx) + log (1.0 - fx[n - i - 1])); */
fn2 = (2.0 * i + 1.0) / (2.0 * n);
sum4 += (fx - fn2) * (fx - fn2);
fn2 = (2.0 * (i + 1) - 1.0) / (2.0 * n);
zbar += fx;
}
zbar /= n;
y[0] = (1.0 / (n * 12) + sum4) - n * (zbar - .5) * (zbar - .5);
y[0] *= 1.0 + 0.16 / n;
#ifdef NOISY
fprintf(stdout, " TEST19 WU2(E) =%10.4f\n", y[0]);
#endif /* NOISY */
free(xcopy);
return y;
}
NULL
#define NULL
Definition ccmath.h:32
Cdhc_dcmp
int Cdhc_dcmp(const void *i, const void *j)
Definition dcmp.c:1
Cdhc_watson_u2_exp
double * Cdhc_watson_u2_exp(double *x, int n)
Definition watsonue.c:6
x
#define x