[R] [R-pkgs] New version of lme4 and new mailing list R-SIG-mixed-models

From: John Maindonald <john.maindonald_at_anu.edu.au>
Date: Sun 28 Jan 2007 - 11:55:15 GMT


Dear Douglas -
I have tried several fits that relate to ch 10 of the 2nd edition of Maindonald & Braun. In two cases a fit that does not currently converge with lmer does now converge with lme2. In one case where I took logs in order to get convergence (the data did not really demand it), I can now get away without taking logs. Basically, none of the problems that I had to work around when I did the calculations for that chapter have surfaced. An exercise that had been problematic now converges without apparent problem.

In one case CPU time was reduced by a factor of around 3. In one case where I formerly could not get convergence, the reduction (to termination of the calculations) was by a factor of around 10. The results seems similar, with a small increase in the loglikelihood (perhaps ~0.5; I have not checked very carefully) in some cases. If you want more detail, I will provide it.

It looks a huge improvement. I am sure that R users will be duly grateful for your efforts.
Regards
John Maindonald.

John Maindonald email: john.maindonald@anu.edu.au phone : +61 2 (6125)3473 fax : +61 2(6125)5549 Centre for Mathematics & Its Applications, Room 1194, John Dedman Mathematical Sciences Building (Building 27) Australian National University, Canberra ACT 0200.

> sessionInfo()

R version 2.4.1 Patched (2007-01-17 r40518) i386-apple-darwin8.8.1

locale:
C

attached base packages:
[1] "stats" "graphics" "grDevices" "datasets" "utils" "methods"
[7] "base"

other attached packages:

        DAAG        MASS        lme4      Matrix     lattice
      "0.91"    "7.2-31" "0.9975-11"  "0.9975-8"   "0.14-16"

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