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Python sympy.stats.NegativeMultinomial()用法及代码示例


借助于sympy.stats.NegativeMultinomial()方法,我们可以创建具有负多项式分布的离散随机变量。

用法:sympy.stats.NegativeMultinomial(syms, k, p)

参数:
 syms:the symbol
 k:number of failures before the experiment is stopped, a positive integer
 p:event probabilites, p>= 0 and p<= 1

返回:a discrete random variable with Negative Multinomial Distribution.

范例1:

Python3

# import sympy, NegativeMultinomia, density, symbols 
from sympy.stats import density 
from sympy.stats.joint_rv_types import NegativeMultinomial 
from sympy import symbols, pprint 
  
p1, p2, p3 = symbols('p1, p2, p3', positive = True) 
x1, x2, x3 = symbols('x1, x2, x3', nonnegative = True, integer = True) 
  
# using sympy.stats.NegativeMultinomial() method 
N = NegativeMultinomial('N', 3, p1, p2, p3) 
negMulti = density(N)(x1, x2, x3) 
  
pprint(negMulti)

输出:

  x1   x2   x3                    3                        
p1  *p2  *p3  *(-p1 - p2 - p3 + 1) *Gamma(x1 + x2 + x3 + 3)
-----------------------------------------------------------
                       2*x1!*x2!*x3!   

范例2:



Python3

# import sympy, NegativeMultinomia, density, symbols 
from sympy.stats import density 
from sympy.stats.joint_rv_types import NegativeMultinomial 
from sympy import symbols, pprint 
  
x1, x2, x3 = symbols('x1, x2, x3', nonnegative = True, integer = True) 
  
# using sympy.stats.NegativeMultinomial() method 
N = NegativeMultinomial('N', 2, 1 / 3, 1 / 2) 
negMulti = density(N)(x1, x2, x3) 
  
pprint(negMulti)

输出:

 -x2  -x1                        
2   *3   *Gamma(x1 + x2 + x3 + 2)
---------------------------------
            36*x1!*x 



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注:本文由纯净天空筛选整理自ravikishor大神的英文原创作品 sympy.stats.NegativeMultinomial() function in Python。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。