Multigrid Restriction Apply

Problem

Apply the 1D multigrid restriction operator to a fine-grid vector of odd length 2m+1, producing a coarse vector of length m:

coarse[i] = 0.25*fine[2i] + 0.5*fine[2i+1] + 0.25*fine[2i+2]

Hint

The stencil [1/4, 1/2, 1/4] smooths the residual onto the coarser grid.

case 1

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

expected: [0.5,0.5]

case 2

in: [[0,0,0]]

expected: [0]

case 3

in: [[1,2,3,4,5]]

expected: [2,4]

case 4

in: [[2,1,2]]

expected: [1.5]

Starter codePython

def multigrid_restrict(fine):
    # Your code here
    pass

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