On 21 Apr 2004, Peter Dalgaard wrote: > [EMAIL PROTECTED] writes: > > > Full_Name: Dr. Hans A. Kestler > > Version: 1.8.1. > > OS: Linux, Win, Mac OSX > > Submission from: (NULL) (134.60.73.116) > > > > > > The code below produces after a different number of iterations i the following > > error: > > > > Error in optim(par = rep(0.5, length(edges)), loglik, method = "L-BFGS-B", : > > non-finite value supplied by optim > > > > This was reproducible on different machines (Mac G4 OSX, AMD Opteron Linux SUSE > > 9.0, Intel P4 Suse 9.0, P4 Windows XP Prof), only with different i. > > > > The non-deterministic behaviour made us recompile R with debug options and use > > valgrind for memory-leak checking. The result was horrible. We are now in the > > process of going through the f2c code of lbfgsb.c. The problem seems to be a > > access violation of wn1 at run time. > > I have this down to the use of R_alloc in the vect() function (line > 40, optim.c). Replacing with S_alloc (which zeros memory) removes the > issue for me on this machine and on the Opteron. Could you please > verify on other platforms? And if anyone actually understands the code > could you verify that it makes sense to require the workspace to be > initialized?
Zeroing the workspace is not a requirement of the original L-BFGS-B code that I can see. Given that it was originally in Fortran, and Fortran often does zero it seems a likely symptom, but it does mean that a variable is being used uninitialized somewhere in the code (converted to C). It would be better to leave vect alone and to zero the workspace with a memset call in lbfgsb. (Incidentally, I don't know why S_alloc does not use memset -- we do require standard C and use in seeral other places.) -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
