Variance Reduction Factor for Gradient Estimators

Problem

Compute the variance reduction factor achieved by an estimator.

Return 1 - var_after / var_before, or 0.0 when var_before is zero. A factor of 1 means the variance was completely eliminated.

Hint

The factor is the fraction of variance removed relative to the baseline.

case 1

in: [1,0.25]

expected: 0.75

case 2

in: [4,1]

expected: 0.75

case 3

in: [2,2]

expected: 0

case 4

in: [0,1]

expected: 0

Starter codePython

def variance_reduction_factor(var_before, var_after):
    # Your code here
    pass

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