[R] I want to use Sweave, but only sometimes

[Paul Johnson]

Does anybody have a workable system to run an Rnw document through
R-Sweave when necessary, but to just run it through LaTeX if no new R
calculations are needed? I.e.,  the figures already exist, I do not
need R to do more work for me, so I send the document straight to
LaTeX.

I want to leave open the option that I might need to run the document
through Sweave in the future, so I don't want to just convert the
document to pure LaTeX format.

Here's why I think this must be possible. In this list, I saw one of
you explain this approach to working with figures in Sweave docs:

Instead of using the automatic figure inclusion approach like this:

<<testfn2, fig=true>>=
curve(sin, from = 1, to = 55)
@

Do this instead:


\SweaveOpts{prefix.string=foo/bar}

<<testfn2, fig=true, include=false>>=
curve(sin, from = 1, to = 55)
@


\begin{figure}
\caption{My Figure}
\includegraphics{foo/bar-testfn}
\end{figure}


As long as the figures are saved in the directory foo, then LaTeX will
find them, I think (hope!).  Then if I could tell LaTeX to ignore the
<<>> ...@ stuff, then it *seems* to me the Rnw file would be processed
successfully without further hassle.

I am sorry if this has been asked & answered before, I may not know
the "magic words" for searching for past solutions.

pj

-- 
Paul E. Johnson
Professor, Political Science
1541 Lilac Lane, Room 504
University of Kansas