2. Sigmoid

Easy

Implement the sigmoid activation function.

Signature: def sigmoid(x: np.ndarray) -> np.ndarray

sigmoid(0) = 0.5

Math

σ (x) = \frac{1}{1 + e ^{- x}}

Related problems

Asked at

Python 30/10 runs today

Output

Anything you print() in your code will show up here after you click Run.

Test Results

○zero input

○positive values

○large values🔒 Premium

○output is non-negative (sigmoid in [0,1])

○preserves argmax (monotonic increasing)

○sigmoid(0) = 0.5 exact

○3D batch (B=2, T=2, C=3) — element-wise works for any rank🔒 Premium