
{{alias}}( x )
    Computes the hyperbolic arctangent of a number.

    The domain of `x` is restricted to `[-1,1]`. If `|x| > 1`, the function
    returns `NaN`.

    Parameters
    ----------
    x: number
        Input value.

    Returns
    -------
    out: number
        Hyperbolic arctangent (in radians).

    Examples
    --------
    > var v = {{alias}}( 0.0 )
    0.0
    > v = {{alias}}( 0.9 )
    ~1.472
    > v = {{alias}}( 1.0 )
    Infinity
    > v = {{alias}}( -1.0 )
    -Infinity
    > v = {{alias}}( NaN )
    NaN

    // The function underflows for small `x`:
    > v = {{alias}}( 1.0e-17 )
    0.0

    See Also
    --------

