Thanks. I was not aware of these subtleties of R, but then again I'm no expert. I had to use isTRUE(all.equal(vec,c(0,0))), but it seems to be working now. Thanks again. -- View this message in context: http://r.789695.n4.nabble.com/Odd-behaviour-of-identical-tp4630118p4630170.html Sent from the R help mailing list archive at Nabble.com.