[Numpy-discussion] Noncentral chi square

[Robert Kern]

On Mon, May 19, 2008 at 11:33 AM, Peck, Jon <peck at spss.com> wrote:
> Message: 1
> Date: Mon, 19 May 2008 09:20:21 -0400
> From: Neal Becker <ndbecker2 at gmail.com>
> Subject: [Numpy-discussion] noncentral_chisquare buglet?
> To: numpy-discussion at scipy.org
> Message-ID: <g0ruqm$ke$1 at ger.gmane.org>
> Content-Type: text/plain; charset=us-ascii
>
>    def noncentral_chisquare(self, df, nonc, size=None):
>        """Noncentral Chi^2 distribution.
>
>        noncentral_chisquare(df, nonc, size=None) -> random values
>        """
>        cdef ndarray odf, ononc
>        cdef double fdf, fnonc
>        fdf = PyFloat_AsDouble(df)
>        fnonc = PyFloat_AsDouble(nonc)
>        if not PyErr_Occurred():
>            if fdf <= 1:
>                raise ValueError("df <= 0") <<<????
>
> I think this message should be "df <= 1"?
>
> [>>>Peck, Jon]
> Isn't it rather that the message is correct but the test is wrong?  Shouldn't it be
> if fdf <= 0  ?

<goes back over assumptions> Yes, you are correct.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
 -- Umberto Eco