On Sat, 2012-04-21 at 17:49 -0700, chris90nz wrote: <...> > I have written the following code which will let me pass it through > using .C > as two vectors, one containing the numbers contained in the lists all > concatenated, the other containing the indicies at which each list > starts. <...> > This approach works, but is still slow (10,000 times doing this takes > ~30seconds). > > I know you can pass a list through by having the C function take as a > parameter SEXP*. However I am not familiar with using Rinternals.h and > am a little lost as to how I would access elements of my big list if I > just pass the whole thing through to a SEXP*. > > The other thing is I have 2 lists to pass through like this, and > another with an arbitrary sized matrix instead of a list of integers, > so I think the only way I can do this efficiently is if I do pass > these lists through to a SEXP*.
The fact that you admit to being 'a little lost' suggests that you should use a higher level interface. The list archives here have a wealth of information, most recently a very good summary of the more modern .Call interface here: http://www.mail-archive.com/r-devel@r-project.org/msg26578.html and here: http://www.mail-archive.com/r-devel@r-project.org/msg26631.html as an even higher level interface, perhaps you should consider RCpp, which contains even more data structures for handling large R data structures, and more hand holding. Reference slides here: http://dirk.eddelbuettel.com/bio/presentations.html (see especially the full day workshop from 2010) Regards, - Brian -- Brian G. Peterson http://braverock.com/brian/ Ph: 773-459-4973 IM: bgpbraverock ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
