LDPC Check-Node Update

Problem

Perform one min-sum check-node update. For each incoming message index i, the outgoing message is the product of the signs of all other messages times the smallest absolute value among the other messages. A single message produces 0.0.

Hint

Every outgoing message excludes its own incoming message.

Test cases

case 1

in: [[1,2,3]]

expected: [2,1,1]

case 2

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

expected: [-2,1,-1]

case 3

in: [[5]]

expected: [0]

case 4

in: [[-2,2]]

expected: [2,-2]

case 5

in: [[0.5,-1.5,2.5]]

expected: [-1.5,0.5,-0.5]

Starter codePython

def ldpc_check_update(messages):
    # Your code here
    pass

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