[Rd] simple tools for extracting call graph information from Rprof output

[Luke Tierney]

A preliminary version of a package proftools for examining Rprof
profiling output and, in particular, extracting and viewing call graph
information is available at

    http://www.stat.uiowa.edu/~luke/R/codetools/proftools.tar.gz

Call graph information, including which direct calls where observed
and how much time was spent in these calls, can be very useful in
identifying performance bottlenecks.  The package produces either
printed representations of the call graph, analogous to the ones
produced by the GNU profiler gprof, or can be used to produce
graphical representations using the Graphviz command line tools or the
Rgraphviz package.

The README file in the package contains some documentation that will
eventually be worked into a vignette.

The implementation is extremely crude (a real mess would be more
accurate) and will hopefully be improved over time--at this point it
is more of an existence proof than a final product.

Performance is less than ideal, though using these tools it was
possible to identify some problem points and speed up computing the
profile data by a factor of two (in other words, it may be bad now but
it used to be worse).  More careful design of the data structures and
memoizing calculations that are now repeated is likely to improve
performance substantially.


luke

-- 
Luke Tierney
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
   Actuarial Science
241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu