[R] lme syntax for P&B examples

Martin Maechler maechler at stat.math.ethz.ch
Thu Feb 9 16:19:41 CET 2006


>>>>> "HaroldD" == Doran, Harold <HDoran at air.org>
>>>>>     on Wed, 8 Feb 2006 08:01:03 -0500 writes:

    HaroldD> ................

    HaroldD> A few thoughts, first, use lmer in the Matrix
    HaroldD> package and not in lme4. 

Well, that's potentially misleading advice:  If both lme4 and
Matrix are (more or less) current, it is actually better to call
library(lme4) if you want to use  lmer() .

A more extensive advice + explanation :

  - "lme4" is the package you should use when using lmer().
    Using "Matrix" *instead* works as well *currently*
    (and yes, *currently* lmer is in the Matrix namespace).

  - At the moment, "lme4" is an almost empty wrapper around using
    package "Matrix", since the C code for lmer() needs to be
    able to call C code inside "Matrix" and that is not yet
    portably possible.
    For that reason, everything for lmer() is currently inside
    "Matrix", but that should change when R will have the
    infrastructure for R packages to export their C API such that
    other R packages can reliably use that C API.


    HaroldD> ................

    HaroldD> Last, a colleague and I have a paper in press
    HaroldD> showing how to fit models using lme which we
    HaroldD> submitted a year or so ago.

    HaroldD> Since lme has evolved to lmer, we created an
    HaroldD> appendix that translates all of our lme models to
    HaroldD> the lmer syntax so readers can see equivalences. I
    HaroldD> am happy to send this to you (or others) upon request.

That sounds quite interesting; I'll be glad to receive it as
well.

Martin Maechler, ETH Zurich


    HaroldD> http://cran.r-project.org/doc/Rnews/Rnews_2005-1.pdf

    HaroldD> Harold




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