Hadamard Transform 4-point

Problem

Multiply a length-4 vector v by the 4-point Hadamard matrix:

H4 = [[1,1,1,1],[1,-1,1,-1],[1,1,-1,-1],[1,-1,-1,1]]

Return H4 * v as a list of four values.

Hint

Each output is a signed sum of the inputs with signs given by a row of H4.

case 1

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

expected: [1,1,1,1]

case 2

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

expected: [4,0,0,0]

case 3

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

expected: [10,-2,-4,0]

case 4

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

expected: [1,-1,-1,1]

Starter codePython

def hadamard_transform_4(v):
    # Your code here
    pass

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