mindspore.ops.polygamma

mindspore.ops.polygamma(n, input)

Computes the $n$-th derivative of the polygamma function on input.

$${\psi }^{(a)}(x)=\frac{d^{(a)}}{d{x}^{(a)}}\psi (x)$$

where $\psi (x)$ is the digamma function.

Parameters

• n (Tensor) – The order of the polygamma function. Supported dtypes: int32, int64. The shape of n is $()$.

• input (Tensor) – The tensor to compute the $n$-th derivative of the polygamma function with.

Returns

Tensor, has the same dtype as input.

Raises

• TypeError – If input is not a Tensor.

• TypeError – If dtype of input is not one of: float16, float32, float64.

• TypeError – If dtype of n is not one of: int32, int64.

• TypeError – If shape of n is not $()$.

Supported Platforms:

GPU CPU

Examples

>>> import mindspore
>>> import numpy as np
>>> from mindspore import Tensor, ops
>>> x = Tensor(np.array([3.14, -2.71]), mindspore.float64)
>>> a = Tensor(np.array(1), mindspore.int64)
>>> output = ops.polygamma(a, x)
>>> print(output)
[ 0.37446456 15.49884838]