On 03/12/2010 10:57 AM, Prof. John C Nash wrote:
No, this is not about Rcpp, but a comment in that overly long discussion raised
a question
that has been in my mind for a while.
This is that one may have work that is used in R in the base functionality and
there are
improvements that should be incorporated.
For me, this concerns the BFGS, Nelder-Mead and CG options of optim(), which
are based on
the 1990 edition (Pascal codes) of my 1979 book "Compact numerical methods...",
which were
themselves derived from other people's work. By the time Brian Ripley took that
work (with
permission, even though not strictly required. Thanks!) there were already some
improvements to these same algorithms (mainly bounds and masks) in the BASIC
codes of the
1987 book by Mary Walker-Smith and I. However, BASIC to R is not something I'd
wish on
anyone.
Now there are some R packages, including some I've been working on, that do
offer
improvements on the optim() offerings. I would not say mine are yet fully ready
for
incorporation into the base, but they are pretty close. Equally I think some of
the tools
in the base should be deprecated and users encouraged to try other routines. It
is also
getting more and more important that novice users be provided with sensible
guidance and
robust default settings and choices. In many areas, users are faced with more
choice than
is efficient for the majority of problems.
My question is: How should such changes be suggested / assisted? It seems to me
that this
is beyond a simple feature request. Some discussion on pros and cons would be
appropriate,
and those like myself who are familiar with particular tools can and should
offer help.
Alternatively, is there a document available in the style "Writing R
Extensions" that has
a title like "How the R Base Packages are Updated"? A brief search was negative.
I'm happy to compete with my own prior work to provide improvements. It would
be nice to
see some of those improvements become the benchmark for further progress.
There are answers at many different levels to your questions. The
simplest is that base packages are part of R, so they get updated when a
member of R Core updates them, and the updates get released when a new
version of R is released.
So if you want a change, you need to convince a member of the core to
make it. Pointing out a bug is the easiest way to do this: bugs
usually get fixed quickly, if they are clearly demonstrated.
If you want a bigger change, you need to make a convincing argument in
favour of it. If you pick a topic that is of particular interest to one
core member, and you can convince him to make the change, then it will
happen. If pick some obscure topic that's not of interest to anyone,
you'll need a very strong argument to make it interesting. Part of any
of these arguments is explaining why the change needs to be made to the
base, why it can't just be published in a contributed package. (That's
why bug fixes are easy, and big additions to the base packages are not.)
Duncan Murdoch
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