Relu3 - An example kernel

def relu3(x: float) -> float:
    """
    Like ReLu, but smoother
    Like GeLu, but cheaper
    """
    if x < 0.0:
        return 0.0
    elif x < 1.0:
        return 1 / 3 * x ** 3
    else:
        return x - 2 / 3

Look, smooth!