Python – tensorflow.math.polygamma()

TensorFlow 是由 Google 设计的开源Python库，用于开发机器学习模型和深度学习神经网络。

polygamma()用于计算 polygamma函数。多伽马函数定义为：

此函数仅针对非负整数订单定义，即 a 的值应为非负数。

Syntax: tensorflow.math.polygamma( a, x, name)

Parameters:

• a: It’s a tensor of non-negative values. Allowed dtyes are  float32, float64.
• x: It’s a tensor of same dtype as a.
• name(optional): It defines the name for the operation.

Returns:

It returns a tensor of same dtype as a.

示例 1：

Python3

# importing the library
import tensorflow as tf
  
# Initializing the input tensor
a = tf.constant([1, 2, 3], dtype = tf.float64)
x = tf.constant([7, 9, 13], dtype = tf.float64)
  
# Printing the input tensor
print('a: ', a)
print('x: ', x)
  
# Calculating result
res = tf.math.polygamma(a, x)
  
# Printing the result
print('Result: ', res)

输出：

a:  tf.Tensor([1. 2. 3.], shape=(3, ), dtype=float64)
x:  tf.Tensor([ 7.  9. 13.], shape=(3, ), dtype=float64)
Result:  tf.Tensor([ 0.15354518 -0.01379332  0.00102074], shape=(3, ), dtype=float64)

示例 2：对于返回输出的负值是 nan。

Python3

# importing the library
import tensorflow as tf
  
# Initializing the input tensor
a = tf.constant([-1, 2, 3], dtype = tf.float64)
x = tf.constant([7, 9, 13], dtype = tf.float64)
  
# Printing the input tensor
print('a: ', a)
print('x: ', x)
  
# Calculating Result
res = tf.math.polygamma(a, x)
  
# Printing the result
print('Result: ', res)

输出：

a:  tf.Tensor([-1.  2.  3.], shape=(3, ), dtype=float64)
x:  tf.Tensor([ 7.  9. 13.], shape=(3, ), dtype=float64)
Result:  tf.Tensor([        nan -0.01379332  0.00102074], shape=(3, ), dtype=float64)