R devel - Feb 2013 - large sysdata.rda file --- strategies?

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

On 07.02.2013 15:41, Dr. Peter Ruckdeschel wrote:
> 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?
Yes, given this package needs less updates than the main package, one 
should consider such a data only package that needs rare updates and 
does not flood the space with archived versions.

> 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.
If the checks will be changed not to warn in such a case, this can only 
happen for R >= 3.0.0, so your workaround to tell the checks you really 
intended such a package with R folder not containing any code sounds 
plausible for now.

> Q2: Is there a lazy load / lazy data mechanism available for
> sysdata.rda ? If so how would one enforce it?
It is lazy loaded. From WRE:
"if the ?R? subdirectory contains a file ?sysdata.rda? [...] this will 
be lazy-loaded into the namespace/package environment"


Best,
Uwe


> Any suggestions appreciated,
>
> Best, Peter
>