Y = ncx2pdf(X,V,DELTA) computes the noncentral chi-square pdf at each of the values in X using the corresponding degrees of freedom in V and positive noncentrality parameters in DELTA. Vector or matrix inputs for X, V, and DELTA must have the same size, which is also the size of Y. A scalar input for X, V, or DELTA is expanded to a constant array with the same dimensions as the other inputs.

Some texts refer to this distribution as the generalized Rayleigh, Rayleigh-Rice, or Rice distribution.

Examples

Compare the noncentral chi-square pdf with DELTA = 2 to the chi-square pdf with the same number of degrees of freedom (4):

x = (0:0.1:10)';
ncx2 = ncx2pdf(x,4,2);
chi2 = chi2pdf(x,4);

plot(x,ncx2,'b-','LineWidth',2)
hold on
plot(x,chi2,'g--','LineWidth',2)
legend('ncx2','chi2')

References

[1] Johnson, N., and S. Kotz. Distributions in Statistics: Continuous Univariate Distributions-2. Hoboken, NJ: John Wiley & Sons, Inc., 1970, pp. 130–148.

ncx2pdf - Noncentral chi-square probability density function

Syntax

Description

Examples

References

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