Chi-square cumulative distribution function
p = chi2cdf(x,v)
p = chi2cdf(x,v,'upper')
p = chi2cdf(x,v) computes the chi-square cdf at each
of the values in
x using the corresponding degrees of freedom in
v can be vectors,
matrices, or multidimensional arrays that have the same size. A scalar input is expanded
to a constant array with the same dimensions as the other input. The degrees of freedom
v must be positive, and the values in
x must lie on the interval
p = chi2cdf(x,v,'upper') returns
the complement of the chi-square cdf at each value in
using an algorithm that more accurately computes the extreme upper
The χ2 cdf for a given value x and degrees-of-freedom ν is
where Γ( · ) is the Gamma function.
The chi-square density function with ν degrees-of-freedom is the same as the gamma density function with parameters ν/2 and 2.
probability = chi2cdf(5,1:5)
probability = 1×5 0.9747 0.9179 0.8282 0.7127 0.5841
probability = chi2cdf(1:5,1:5)
probability = 1×5 0.6827 0.6321 0.6084 0.5940 0.5841
This function fully supports GPU arrays. For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).