[Expm-developers] R package 'expm' - release to CRAN?

Martin Maechler maechler at stat.math.ethz.ch
Fri Jun 18 12:47:50 CEST 2010

Dear 'expm' co-developers,

After Michael Stadelmanns master thesis finished here at ETH,
more than a year ago, which provided one or two new state-of-the-art matrix
exponential algorithms, and the Matrix-Log + Matrix-Sqrt,
not much has happened
though I've noticed that Nick Higham has produced yet another
improvement to his algorithm, namely: 
    author =    {Awad H. Al-Mohy and Nicholas J. Higham},
    year =      2009,
    title =     {A New Scaling and Squaring Algorithm for the Matrix Exponential},
    journal =   {SIAM Journal on Matrix Analysis and Applications},
    volume =    31,
    number =    3,
    pages =     {970-989},

( I have added the reference to expm/inst/doc/expm.bib )

But our 'expm' package is still only on R-forge and hence not
really much visible in the R using comunity.
Also, the recommended Matrix package which has provided expm()
for a long time, still only provides "Ward77"
which is clearly sub-optimal given Higham's work.

OTOH, in some way, 'expm' is now an "extension" to the Matrix package
(as it 'Depends' on it anyway, e.g. for using  Matrix::norm()),
providing extra features.

In light of this, I'd like to release 'expm' to CRAN
ASAP, and just wanted to get feedback from you before doing

Best regards,

Martin <Maechler at stat.math.ethz.ch>  http://stat.ethz.ch/people/maechler
Seminar für Statistik, ETH Zürich  HG G 16      Rämistrasse 101
phone: +41-44-632-3408       fax: ...-1228      <><

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