Sqrl - An example tensor-to-tensor kernel

@knossos.register
def sqrl(x: torch.Tensor):
    """
    sqrl: Squared Leaky Relu
    Like a capsule from /Stuck in a Rut/
    Typically x is a 4x4 tensor, possibly
    packed in a 4n x 4m array
    """
    y = torch.sum(x)
    if y < 0.0:
        t = -0.125 * x
    else:
        t = 1 / 2 * x ** 2
    return torch.mean(torch.sin(t) * t)