Hi Elizabeth, I just found your thread after experiencing a similar problem (I was also using some IRanges/GenomicRanges functions). You've probably figured it out by this time - I'm actually curious to know what you found?
I think I've tracked it down in my case, where a small minority of the elements I was trying to lapply/mclapply over caused a genuine error (perhaps in your case a genuine NULL answer - is that possible?). When I used lapply that error was very obvious - it came up on the screen. But when I used mclapply it looked like the function completed fine - it wasn't until later that I saw the error was captured as a string object in the relevant slot of the list object returned by mclapply. I should build in some checking if I want to persist with using mclapply. I wonder if something similar is going on in your case? Janet ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
