Subgradient Absolute Value Step

Problem

For f(x) = |x|, a subgradient at x is sign(x) with 0 chosen at the kink. One subgradient step is x_new = x - lr * sign(x).

Given x and lr, return x_new.

Hint

The kink is already a minimum, so it stays put.

case 1

in: [2,0.5]

expected: 1.5

case 2

in: [-1,2]

expected: 1

case 3

in: [0,1]

expected: 0

Starter codePython

def subgradient_absolute_value_step(x, lr):
    # Your code here
    pass

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