Python math.gamma() 方法

Python的语言允许各种数学运算，在科学领域有多种应用。 Python的一个这样的产品是内置的gamma()函数，它以数值方式计算函数中传递的数字的 gamma 值。

Syntax : math.gamma(x)
Parameters :
x : The number whose gamma value needs to be computed.

Returns : The gamma value, which is numerically equal to “factorial(x-1)”.

代码 #1：演示 gamma() 的工作原理

# Python code to demonstrate
# working of gamma()
import math
  
# initializing argument
gamma_var = 6
  
# Printing the gamma value.
print ("The gamma value of the given argument is : "
                       + str(math.gamma(gamma_var)))

输出：

The gamma value of the given argument is : 120.0

阶乘（）与伽玛（）

gamma 值也可以使用factorial(x-1)找到，但gamma()的用例是因为，如果我们比较两个函数以实现相似的任务， gamma()提供更好的性能。

代码 #2：比较factorial()和gamma()

# Python code to demonstrate
# factorial() vs gamma()
import math
import time 
  
# initializing argument
gamma_var = 6
  
# checking performance 
# gamma() vs factorial()
start_fact = time.time()
res_fact = math.factorial(gamma_var-1)
  
print ("The gamma value using factorial is : " 
                              + str(res_fact))
  
print ("The time taken to compute is : "
        + str(time.time() - start_fact))
  
print ('\n')
  
start_gamma = time.time()
res_gamma = math.gamma(gamma_var)
  
print ("The gamma value using gamma() is : "
                           + str(res_gamma))
  
print ("The time taken to compute is : " 
       + str(time.time() - start_gamma))

输出：

The gamma value using factorial is : 120
The time taken to compute is : 9.059906005859375e-06

The gamma value using gamma() is : 120.0
The time taken to compute is : 5.245208740234375e-06