keras/src/activations/activations.py/elu
def elu(x, alpha=1.0):
    """Exponential Linear Unit.

    The exponential linear unit (ELU) with `alpha > 0` is define as:

    - `x` if `x > 0`
    - alpha * `exp(x) - 1` if `x < 0`

    ELUs have negative values which pushes the mean of the activations
    closer to zero.

    Mean activations that are closer to zero enable faster learning as they
    bring the gradient closer to the natural gradient.
    ELUs saturate to a negative value when the argument gets smaller.
    Saturation means a small derivative which decreases the variation
    and the information that is propagated to the next layer.

    Args:
        x: Input tensor.

    Reference:

    - [Clevert et al., 2016](https://arxiv.org/abs/1511.07289)
    """
    return ops.elu(x, alpha=alpha)