Stefano, i notice that my and Bill's (pretty much isomorphic) solutions give a zero-length vector. i don't remember Bert's, but it's probably gives similar results. your code could check for that result, and react accordingly.
cheers, Greg ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
