mindspore.nn.IGamma

class mindspore.nn.IGamma[source]

Calculates lower regularized incomplete Gamma function. The lower regularized incomplete Gamma function is defined as:

\[P(a, x) = gamma(a, x) / Gamma(a) = 1 - Q(a, x)\]

where

\[gamma(a, x) = \int_0^x t^{a-1} \exp^{-t} dt\]

is the lower incomplete Gamma function.

Above \(Q(a, x)\) is the upper regularized complete Gamma function.

Inputs:

a (Tensor) - The input tensor. With float32 data type. a should have the same dtype with x.
x (Tensor) - The input tensor. With float32 data type. x should have the same dtype with a.

Outputs:

Tensor, has the same dtype as a and x.

Raises: TypeError – If dtype of input x and a is not float16 nor float32, or if x has different dtype with a.

Supported Platforms:: Ascend GPU

Examples

>>> a = Tensor(np.array([2.0, 4.0, 6.0, 8.0]).astype(np.float32))
>>> x = Tensor(np.array([2.0, 3.0, 4.0, 5.0]).astype(np.float32))
>>> igamma = nn.IGamma()
>>> output = igamma(a, x)
>>> print (output)
[0.593994  0.35276785  0.21486944  0.13337152]