Message-ID: <x2aezn5viz.fsf@blueberry.kubism.ku.dk>
Date: 1999-01-13T10:15:00Z
From: Peter Dalgaard
Subject: a bug and a question
In-Reply-To: Jim Lindsey's message of Wed, 13 Jan 1999 08:58:10 +0100 (MET)
Jim Lindsey <jlindsey at alpha.luc.ac.be> writes:
> The question: I am getting various reports that R under MS-Windows and
> X-Windows/Linux on the same machine behaves very differently for nlm
> convergence in my libraries. Under Linux, convergence is easy with
> many starting values, but under MS they have to be very close to the
> MLE. Does anyone have experience with this and or an explanation?
> Is the math used different in the two systems?
> Jim
Not entirely unlikely. The FPU should be the same of course, but the C
and math libraries link to a Microsoft DLL, which I have heard people
speak badly about before.
Particularly the IEEE exception handling could be causing trouble if
an iterative method wanders near the boundary of a functions domain.
That is pure speculation, though, I suppose Guido and Brian will know
more.
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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