Particle Filter Weight Normalization

Problem

Normalize a list of particle weights so they sum to one by dividing each weight by the total. If the total weight is not positive, including an all-zero list, return a uniform distribution over the particles instead.

Return an empty list for empty input.

Hint

Degenerate weights fall back to a uniform distribution so the filter never stalls.

Test cases

case 1

in: [[1,1,2]]

expected: [0.25,0.25,0.5]

case 2

in: [[2,3]]

expected: [0.4,0.6]

case 3

in: [[0,0]]

expected: [0.5,0.5]

case 4

in: [[]]

expected: []

case 5

in: [[1,2,0]]

expected: [0.3333333333333333,0.6666666666666666,0]

Starter codePython

def particle_weight_normalization(weights):
    # Your code here
    pass

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