Date: Fri, 20 Sep 1996 11:08:38 -0700 (PDT) From: Thomas Lumley <thomas@biostat.washington.edu> To: r-testers@stat.math.ethz.ch Subject: R-alpha: more little problems In-Reply-To: <199609200415.QAA02569@stat.auckland.ac.nz> 1. pmin and pmax coerce matrices to vectors. This is incompatible with S. The documentation says they work on vectors, and as is.vector() returns TRUE for a matrix it is not completely unreasonable that they should work on matrices. It's also massively useful. A first pass at fixing this is to make the following insertions near the end of pmax and pmin respectively: pmax: ----------------------------- maxmm <- work[, 1] } attributes(maxmm)<-attributes(elts[[1]]) ###insert maxmm } ----------------------------- pmin: ----------------------------- minmm <- work[, 1] } attributes(minmm)<-attributes(elts[[1]]) ###insert minmm } ---------------------------- Of course ideally we should check that all the dimensions are either the same or NULL. 2. model.matrix(formula, data) does not use the names of the data frame it is passed (unlike in S). It assumes that the variables in the formula start at column 1 of the data frame and proceed in order. This works correctly in the standard situation when data comes from model.frame(formula) but can be a problem if the data frame was constructed in some other way. In particular if the data frame has a response and the formula does not, you will get the wrong answer with no error message. Other manipulations of a formula have the same implications. thomas lumley Penguin: the name is supposed to come from PhD student the Welsh _pen_gwyn_ meaning "white head". Biostatistics As penguins have black heads and do not live U. Washington within 10000 miles of Wales it is difficult Seattle WA 98195 to see how this theory arose. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- r-testers mailing list -- To (un)subscribe, send subscribe or unsubscribe (in the "body", not the subject !) To: r-testers-request@stat.math.ethz.ch =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-