Hi! I noticed that there is a (minor) bug either the command all.equal() or in the "plm" package. I demonstrate this using an example taken from the documentation of plm():
====================================== R> data("Produc", package="plm") R> zz <- plm(log(gsp)~log(pcap)+log(pc)+log(emp)+unemp, + data=Produc, index=c("state","year")) R> all.equal(zz,zz) [1] TRUE Warning message: In if (length(target) != length(current)) return(paste("target, current differ in having response: ", : the condition has length > 1 and only the first element will be used > all.equal(zz$formula,zz$formula) [1] TRUE Warning message: In if (length(target) != length(current)) return(paste("target, current differ in having response: ", : the condition has length > 1 and only the first element will be used > class(zz$formula) [1] "pFormula" "Formula" "formula" ====================================== The last commands show that the warning message comes from comparing the elements "formula", which are of the class "pFormula" (inheriting from "Formula" and "formula"). It would be great if this issue could be fixed in the future. Thanks a lot, Arne -- Arne Henningsen http://www.arne-henningsen.name ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel