Dear all, I stumbled over the fact that sweep in fact calls FUN with appropriate arrays. I used to think of it as apply-like to call a function with n-dimensional and n-1-dimensional arguments. I suggest to put a sentence like: sweep appropriately repeats STATS, and calls FUN with two arrays of the same size. into the help page to clarify what input FUN should expect. Claudia -- Claudia Beleites Dipartimento dei Materiali e delle Risorse Naturali Universit? degli Studi di Trieste Via Alfonso Valerio 6/a I-34127 Trieste phone: +39 0 40 5 58-37 68 email: cbeleites at units.it