Perplexity from Cross-Entropy

Problem

Convert a cross-entropy measured in bits to perplexity:

perplexity = 2^CE

Smaller values indicate a better model.

Hint

A model that assigns probability 1 to every observed token has perplexity 1.

case 1

in: [0]

expected: 1

case 2

in: [3]

expected: 8

case 3

in: [2.5]

expected: 5.656854249492381

case 4

in: [10]

expected: 1024

Starter codePython

def perplexity_from_cross_entropy(ce):
    # Your code here
    pass

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