Message-ID: <x27jr7xs4x.fsf@biostat.ku.dk>
Date: 2004-09-06T18:46:23Z
From: Peter Dalgaard
Subject: qchisq (PR#7212)
In-Reply-To: <20040906162516.C86A110EA1@slim.kubism.ku.dk>
david.clayton@cimr.cam.ac.uk writes:
> Full_Name: David Clayton
> Version: 1.8.1
....
> qchisq behaves very strangely when ncp is passed as zero (forcing internal
> qnchisq to be called) when first argument is small.
>
> Eg
>
>
> > qchisq(1-1e-6, 1, ncp=0, lower.tail=TRUE)
> qchisq(1-1e-6, 1, ncp=0, lower.tail=TRUE)
> [1] 1024
>
> while, if ncp is unspecified,
>
> > qchisq(1-1e-6, 1)
> qchisq(1-1e-6, 1)
> [1] 23.92813
As Brian once put it, we can't fix old versions retroactively. 1.9.1
has (on "Linux" as well, although that is a bit unspecific for numeric
issues).
> qchisq(1-1e-6, 1, ncp=0, lower.tail=TRUE)
[1] 23.92813
> qchisq(1-1e-6, 1)
[1] 23.92813
Possibly, this is a side effect of
o qchisq(1-e, .., ncp=.) did not terminate for small e.
(PR#6421 (PR#875))
from BUG FIXES for 1.9.0.
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907