From ripley at stats.ox.ac.uk  Wed Jun 11 09:18:49 2003
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Wed Jun 11 23:38:40 2003
Subject: [Rd] bug in glm()? (PR#3223)
In-Reply-To: <200306102146.h5ALk82b011843@pubhealth.ku.dk>
Message-ID: <Pine.LNX.4.44.0306110812520.12516-100000@gannet.stats>

Could you please supply an example?

1) There is nothing we can reproduce here (see the FAQ on BUGS), and

2) we don't take SAS as the gold standard, and

3) R does have glm.control() to control how convergence is determined, and
you do sometimes need to work with it.

There are models/datasets which do not have an MLE within the parameter 
set: for those R does converge to a value near the boundary.  But R
*should* converge then.  There are also situations in which R will 
converge (correctly) but simple IRLS will not.

On Tue, 10 Jun 2003 bonnie.lafleur@vanderbilt.edu wrote:

> Full_Name: Bonnie 
> Version: 1.6.1
> OS: Windows
> Submission from: (NULL) (160.129.25.106)
> 
> 
> glm() seems to converge, even when it shouldn't.  I am trying to fit a model
> where $converge=FALSE and I am fitting models that do not converge in SAS,
> but they seem to converge in R ...

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


[Rd] bug in glm()? (PR#3223)
Prof Brian Ripley