Dominant Frequency

Problem

Find the dominant frequency of a series by scanning the periodogram bins k = 0, ..., n//2 and returning the normalized frequency k/n at the bin with the largest power. Ties keep the smallest k.

Return 0.0 for a series with fewer than two points.

Hint

A value of 0.5 corresponds to the Nyquist frequency.

Test cases

case 1

in: [[0,1,0,1]]

expected: 0

case 2

in: [[5,5,5,5]]

expected: 0

case 3

in: [[1,2,3,4]]

expected: 0

case 4

in: [[1,-1,1,-1]]

expected: 0.5

case 5

in: [[1,0,-1,0]]

expected: 0.25

Starter codePython

import math
def dominant_frequency(series):
    # Your code here
    pass

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