[Rd] large sysdata.rda file --- strategies?

[Dr. Peter Ruckdeschel]

Hi,

to speed up computations in our RobASt family of packages, we use
interpolation on a grid of precomputed values which we save together
with the interpolating functions (results of splinefun essentially)
in sysdata.rda in the R folder of our pkg.

After adding grids for some more models, this file has grown
considerably, even after application of tools::resaveRdaFiles.
At the moment we are at about 2MB (compressed) and 8.8 MB
(uncompressed) and hence R CMD check --as-cran issues a NOTE.

We want to comply with cran policies,
      http://cran.r-project.org/web/packages/policies.html
in particular with
> Where a large amount of data is required (even after compression),
> consideration should be given to a separate data-only package which
> can be updated only rarely (since older versions of packages are
> archived in perpetuity).

Q1: Are packages only consisting of a sysdata.rda file thinkable for
submission on CRAN ? Are such pkgs the way to go for w.r.t. to the
cited policy?

If this is the case, how  would one document such a package, in particular
if we do not export any objects in the NAMESPACE file?
In addition, with a sysdata.rda-only pkg,  R CMD check issues a warning
"Found directory 'R' with no source files"  Of course a workaround is
adding a comment-only file comment.R to the R folder.

Q2: Is there a lazy load / lazy data mechanism available for
sysdata.rda ? If so how would one enforce it?

Any suggestions appreciated,

Best, Peter

-- 
Dr. habil. Peter Ruckdeschel, Abteilung Finanzmathematik, F3.17
Fraunhofer ITWM, Fraunhofer Platz 1, 67663 Kaiserslautern
Telefon:  +49 631/31600-4699   Fax    :  +49 631/31600-5699
E-Mail :  peter.ruckdeschel at itwm.fraunhofer.de
http://www.itwm.fraunhofer.de/abteilungen/finanzmathematik/mitarbeiterinnen/mitarbeiter/dr-peter-ruckdeschel.html