Tanh (Vector)

Problem

Apply the hyperbolic tangent element-wise: tanh(x) = (exp(x) - exp(-x)) / (exp(x) + exp(-x)).

The signature is tanh_vector(x). Use a numerically stable branch so that large magnitudes saturate to 1.0 or -1.0 instead of overflowing.

Hint

Use exp(-2x) for x >= 0 so the exponent never overflows.

case 1

in: [[0]]

expected: [0]

case 2

in: [[1000,-1000]]

expected: [1,-1]

case 3

in: [[1,-1]]

expected: [0.761594156,-0.761594156]

case 4

in: [[0.5,2,-0.25]]

expected: [0.4621171573,0.9640275801,-0.2449186624]

Starter codePython

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

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