Chi-squared Distribution

Name

UxHwDoubleChiSquaredDist, UxHwFloatChiSquaredDist — Create an $\chi^2$ distribution.

Synopsis

#include <uxhw.h>

double  UxHwDoubleChiSquaredDist(double k);
float   UxHwFloatChiSquaredDist(float k);

Description

The UxHwDoubleChiSquaredDist() function, on architectures that associate distributional information with floating-point values, creates a $\chi^2$ distribution with parameter k and associates it with its return value. The particle return value is the mean value of a $\chi^2$ distribution with parameter k. The probability density function of the $\chi^2$ distribution is

$$f(x;k)= \begin{cases} \frac{1}{\Gamma(k/2)2^k}x^{k/2-1}e^{-x/2} & x\ge 0, \\ 0 & x < 0. \end{cases}$$

Parameters

• k — The parameter ($k$) of the $\chi^2$ distribution.

Return Values

The UxHwDoubleChiSquaredDist() function returns the mean of samples of a $\chi^2$ distribution with parameter k. If k <= 0, the function returns NaN.

✏️   Examples

#include <stdio.h>
#include <uxhw.h>

int
main(void)
{
    double  value = UxHwDoubleChiSquaredDist(1.0);
    printf("value = %lf\n", value);

    return 0;
}