the Box-Cox transformation of 1 + `x`.

    The Box-Cox transformation computed by `boxcox1p` is::

        y = ((1+x)**lmbda - 1) / lmbda  if lmbda != 0
            log(1+x)                    if lmbda == 0

    Returns `nan` if ``x < -1``.
    Returns `-inf` if ``x == -1`` and ``lmbda < 0``.

    Parameters
    ----------
    x : array_like
        Data to be transformed.
    lmbda : array_like
        Power parameter of the Box-Cox transform.
    out : ndarray, optional
        Optional output array for the function values

    Returns
    -------
    y : scalar or ndarray
        Transformed data.

    Notes
    -----

    .. versionadded:: 0.14.0

    Examples
    --------
    >>> from scipy.special import boxcox1p
    >>> boxcox1p(1e-4, [0, 0.5, 1])
    array([  9.99950003e-05,   9.99975001e-05,   1.00000000e-04])
    >>> boxcox1p([0.01, 0.1], 0.25)
    array([ 0.00996272,  0.09645476])
    Ú
inv_boxcoxaö