Convolution Matrix Build

Problem

Build the n x n lower-triangular Toeplitz matrix that performs causal convolution with the given kernel:

C[i][j] = kernel[i - j] when 0 <= i - j < len(kernel), else 0.

Hint

Each column of the convolution matrix is a shifted copy of the kernel.

case 1

in: [[1,2],3]

expected: [[1,0,0],[2,1,0],[0,2,1]]

case 2

in: [[1],2]

expected: [[1,0],[0,1]]

case 3

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

expected: [[1,0,0],[2,1,0],[3,2,1]]

case 4

in: [[2,0,1],4]

expected: [[2,0,0,0],[0,2,0,0],[1,0,2,0],[0,1,0,2]]

Starter codePython

def convolution_matrix(kernel, n):
    # Your code here
    pass

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