GELU (Tanh Approximation)

Problem

Apply the tanh approximation of GELU element-wise: 0.5 * x * (1 + tanh(sqrt(2 / pi) * (x + 0.044715 * x^3))).

The signature is gelu(x). Return a list of the same length.

Hint

The cubic term inside tanh is what distinguishes this approximation from plain tanh gating.

case 1

in: [[0]]

expected: [0]

case 2

in: [[1,-1]]

expected: [0.8411919906,-0.1588080094]

case 3

in: [[2,-2,0.5]]

expected: [1.9545976941,-0.0454023059,0.3457140098]

case 4

in: [[100,-100]]

expected: [100,0]

Starter codePython

import math
def gelu(x):
    # Your code here
    pass

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