
{{alias}}( F )
    Computes the Fibonacci number index.

    If not provided a nonnegative integer value, the function returns `NaN`.

    If provided `F <= 1` or `NaN`, the function returns `NaN`.

    Parameters
    ----------
    F: integer
        Fibonacci number.

    Returns
    -------
    n: number
        Fibonacci number index.

    Examples
    --------
    > var n = {{alias}}( 2 )
    3
    > n = {{alias}}( 3 )
    4
    > n = {{alias}}( 5 )
    5
    > n = {{alias}}( NaN )
    NaN
    > n = {{alias}}( 1 )
    NaN

    See Also
    --------

