//! Activation functions.
use crateTensor;
/// Element-wise ReLU: `max(0, x)`.
/// Element-wise Sigmoid: `1 / (1 + exp(-x))`.
/// Element-wise Tanh: `tanh(x)`.
/// Element-wise GELU (tanh approximation):
/// `0.5 * x * (1 + tanh(sqrt(2/pi) * (x + 0.044715 * x^3)))`.
/// Element-wise Leaky ReLU: `max(alpha * x, x)`.