KID Polynomial Lite

Problem

Compute the polynomial-kernel MMD used by KID.

K(a, b) = (a . b / d + 1)^degree with d the feature dimension; return mean K(s, s') + mean K(t, t') - 2 * mean K(s, t) rounded to 4 decimal places, averaging over ordered pairs including self-pairs.

Test cases

case 1

in: [[[0,0],[1,0]],[[0,0],[1,0]],2]

expected: 0

case 2

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

expected: 0.5

case 3

in: [[[1,2]],[[2,1]],2]

expected: 6.5

Starter codePython

def kid_polynomial(source, target, degree):
    # Your code here
    pass

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