def lagweight(x):
w = np.exp(-x)<EOL>return w<EOL>
Weight function of the Laguerre polynomials.

    The weight function is :math:`exp(-x)` and the interval of integration
    is :math:`[0, \inf]`. The Laguerre polynomials are orthogonal, but not
    normalized, with respect to this weight function.

    Parameters
    ----------
    x : array_like
       Values at which the weight function will be computed.

    Returns
    -------
    w : ndarray
       The weight function at `x`.

    Notes
    -----

    .. versionadded::1.7.0