Croston Method Lite

Problem

Run lite Croston's method for intermittent demand. Each nonzero demand updates a demand-size estimate with smoothing alpha, and together with the gap since the previous nonzero demand updates an interval estimate the same way. Return the ratio size / interval.

Return 0.0 if the series contains no nonzero demand.

Hint

Croston smooths demand size and inter-arrival gap separately.

Test cases

case 1

in: [[0,0,4,0,0,6,0,2],0.5]

expected: 1.4

case 2

in: [[0,0,0],0.3]

expected: 0

case 3

in: [[5],0.5]

expected: 5

case 4

in: [[0,3,0,0,6,0],0.5]

expected: 1.8

Starter codePython

def croston_method(series, alpha):
    # Your code here
    pass

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