mars.tensor.special.gammaincc#

mars.tensor.special.gammaincc(a, b, **kwargs)[source]#

Regularized lower incomplete gamma function.

It is defined as

\[P(a, x) = \frac{1}{\Gamma(a)} \int_0^x t^{a - 1}e^{-t} dt\]

for \(a > 0\) and \(x \geq 0\). See [dlmf] for details.

Parameters

Returns

Values of the lower incomplete gamma function

Return type

scalar or ndarray

Notes

The function satisfies the relation gammainc(a, x) + gammaincc(a, x) = 1 where gammaincc is the regularized upper incomplete gamma function.

The implementation largely follows that of [boost].