Python Scipy stats.erlang()用法及代码示例

scipy.stats.erlang()：是一个Erlang连续随机变量，使用标准格式和一些形状参数定义它以完成其规格。这是Gamma分布的特例。

代码1：创建erlang连续随机变量

from scipy.stats import erlang  
  
numargs = erlang.numargs 
[a] = [0.6, ] * numargs 
rv = erlang(a) 
  
print ("RV : \n", rv) 

输出：

RV : 
 <scipy.stats._distn_infrastructure.rv_frozen object at 0x0000018D544FBC88>

代码2：Erlang随机变量和概率分布。

import numpy as np 
quantile = np.arange (0.01, 1, 0.1) 
   
# Random Variates 
R = erlang.rvs(a, scale = 2,  size = 10) 
print ("Random Variates : \n", R) 
  
# PDF 
R = erlang.pdf(a, quantile, loc = 0, scale = 1) 
print ("\nProbability Distribution : \n", R)

输出：

Random Variates : 
 [5.65708510e+00 5.16045580e+00 1.02056956e-01 3.64349340e-01
 5.65593073e+00 2.27100280e+00 9.77623414e-04 2.01994399e-01
 8.84331471e-01 2.20817630e+00]

Probability Distribution :
[0.01, 0.11, 0.21, 0.31, 0.41, 0.51, 0.61, 0.71, 0.81, 0.91]
 

代码3：图形表示。

import numpy as np 
import matplotlib.pyplot as plt 
  
distribution = np.linspace(0, np.minimum(rv.dist.b, 5)) 
print("Distribution : \n", distribution) 
  
plot = plt.plot(distribution, rv.pdf(distribution))

输出：

Distribution : 
Distribution : 
 [0.         0.10204082 0.20408163 0.30612245 0.40816327 0.51020408
 0.6122449  0.71428571 0.81632653 0.91836735 1.02040816 1.12244898
 1.2244898  1.32653061 1.42857143 1.53061224 1.63265306 1.73469388
 1.83673469 1.93877551 2.04081633 2.14285714 2.24489796 2.34693878
 2.44897959 2.55102041 2.65306122 2.75510204 2.85714286 2.95918367
 3.06122449 3.16326531 3.26530612 3.36734694 3.46938776 3.57142857
 3.67346939 3.7755102  3.87755102 3.97959184 4.08163265 4.18367347
 4.28571429 4.3877551  4.48979592 4.59183673 4.69387755 4.79591837
 4.89795918 5.        ]

代码4：改变位置参数

import matplotlib.pyplot as plt 
import numpy as np 
  
x = np.linspace(0, 5, 100) 
  
# Varying positional arguments 
y1 = erlang.pdf(x, 2, 6) 
y2 = erlang.pdf(x, 1, 4) 
plt.plot(x, y1, "*", x, y2, "r--")

输出：