{{alias}}( s )
    Evaluates the Dirichlet eta function as a function of a real variable `s`.

    Parameters
    ----------
    s: number
        Input value.

    Returns
    -------
    y: number
        Function value.

    Examples
    --------
    > var y = {{alias}}( 0.0 )
    0.5
    > y = {{alias}}( -1.0 )
    0.25
    > y = {{alias}}( 1.0 )
    ~0.6931
    > y = {{alias}}( 3.14 )
    ~0.9096
    > y = {{alias}}( NaN )
    NaN

    See Also
    --------