MediumProbabilitypr-079

Beta PDF Value

Problem

Beta probability density with shape parameters alpha and beta at x:

f(x) = x^(alpha - 1) * (1 - x)^(beta - 1) / B(alpha, beta).

Return 0.0 when x is outside [0, 1] or a parameter is nonpositive; boundary points return 0.0.

Hint

Compute in log space and exponentiate to avoid overflow.

case 1

in: [1,1,0.5]

expected: 1

case 2

in: [2,3,0.5]

expected: 1.4999999999999991

case 3

in: [2,2,0.5]

expected: 1.5

case 4

in: [0,1,0.5]

expected: 0

Starter codePython

import math


def beta_pdf_value(alpha, beta, x):
    # Your code here
    pass

4 test cases · run your code against them in the editor