From bonnie.lafleur at vanderbilt.edu  Wed Jun 11 18:37:24 2003
From: bonnie.lafleur at vanderbilt.edu (bonnie.lafleur@vanderbilt.edu)
Date: Wed Jun 11 23:50:16 2003
Subject: [Rd] bug in glm()? (PR#3223)
Message-ID: <200306111537.h5BFbO2b021879@pubhealth.ku.dk>

Full_Name: Bonnie LaFleur
Version: 1.6.1
OS: Windows
Submission from: (NULL) (160.129.25.106)


All,

I sincerely apologize for being so vague with my "bugs" query.  Part of this
is that it is not directly related to a specific data analysis, but rather
a part of a bigger project I am working on.  I also apologize if the bugs
forum is not appropriate for this problem.  Thank you Prof Brian Ripley for
your point to the glm.control() command, I will work with this for now and
it will solve my most immediate problems.

Specifically, I am running about 10,000 + permutations through an R program
on a bewoulf cluster of machines, and needed to get a handle on whether the
lines and columns of my report output file are consistant, so I can use this
in debugging the overall program for the parallel processing, as well as 
to keep track of any permutations for which a nonlinear program may not
converge.
In trying to answer the number of columns question I tried to find a problem
which I pretty much know has no reason to converge.  It is totally nonsensical
data (as you
can tell).  It does not converge in SAS or Splus for Windows, it does however
converge in R (version 1.6.1) for Windows and R (version 1.3.1) on linux -
though, of course the  stimates are obviously suspect.  I am enclosing simple R
commands 
for these silly data for your perusal.  Thank you for you time, and again, 
I am sorry for the premature post last night.


Bonnie



R : Version 1.3.1 (2001-08-31) (on linux)

Y <- c(1,1,1,1,0)
X1 <- factor(c(0,0,0,1,1))
X2 <- factor(c(0,0,1,0,0))

logist<- glm(Y ~ X1*X2, family=binomial(link="logit"))
summary(logist)
   ## usual logistic output
logist$converged
  ## TRUE

_______________________________________________________

Alternatively in S-Plus, the same model produces a warning message that 
linear convergence was not obtained in
10 iterations.
S-PLUS 2000 professional release 1


[Rd] bug in glm()? (PR#3223)
bonnie.lafleur@vanderbilt.edu