I would like to suggest a slight modification to diag(). In the case
where x is a matrix with both row names and column names the same, it
would be reasonable if the resulting vector also had those names. I often
use diag() on variance matrices, where this modification is helpful.
The modification requires replacing
if (is.matrix(x) && nargs() == 1)
return(c(x)[1 + 0:(min(dim(x)) - 1) * (dim(x)[1] + 1)])
the first two lines, with something like
if (is.matrix(x) && nargs() == 1) {
y <- c(x)[1 + 0:(min(dim(x)) - 1) * (dim(x)[1] + 1)]
if (!is.null(nms <- dimnames(x)) && all(nms[[1]]==nms[[2]]))
names(y) <- nms[[1]]
return(y)
}
Just a thought, Jonathan.
Jonathan Rougier Science Laboratories
Department of Mathematical Sciences South Road
University of Durham Durham DH1 3LE
"[B]egin upon the precept ... that the things we see are to be
weighed in the scale with what we know" (Meredith, 1879, The Egoist)
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>>>>> On Wed, 18 Aug 1999 09:26:42 +0100 (BST), Jonathan Rougier <J.C.Rougier@durham.ac.uk> said:JonR> I would like to suggest a slight modification to diag(). In the JonR> case where x is a matrix with both row names and column names the JonR> same, it would be reasonable if the resulting vector also had JonR> those names. I often use diag() on variance matrices, where this JonR> modification is helpful. JonR> The modification requires replacing JonR> if (is.matrix(x) && nargs() == 1) JonR> return(c(x)[1 + 0:(min(dim(x)) - 1) * (dim(x)[1] + 1)]) JonR> the first two lines, with something like JonR> if (is.matrix(x) && nargs() == 1) { JonR> y <- c(x)[1 + 0:(min(dim(x)) - 1) * (dim(x)[1] + 1)] JonR> if (!is.null(nms <- dimnames(x)) && all(nms[[1]]==nms[[2]])) JonR> names(y) <- nms[[1]] JonR> return(y) JonR> } JonR> Just a thought, Jonathan. JonR> Jonathan Rougier Science Laboratories JonR> Department of Mathematical Sciences South Road JonR> University of Durham Durham DH1 3LE This seems like a good idea [ and I think I vaguely remember that I would have wanted that myself, some time], however, R 0.65 is in ``feature freeze'' now (and release date is scheduled for Aug.27 ..) Yes, please ``everyone'' : Now is pre-tester time, Get "R-devel.tar.gz" from a CRAN site near you, unpack and install {from source!!}, and send bug reports to R-core or R-devel, *not* to R-bugs -- since bugs in non-released versions shouldn't make it into the R repository I think. {I hope to not forget to put the above diag() improvement into the next release after 0.65(.0)..} Martin. -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Hi Martin,
Just to follow my previous suggestion to modify diag(), the code I
suggested is vulnerable to matrices with dimnames(x) <- list(NULL, NULL),
which does occasionally happen (it has just happened to me!), so the
following would be better ...
"diag" <-
function (x = 1, nrow, ncol = n)
{
if (is.matrix(x) && nargs() == 1) {
md <- min(dim(x))
y <- c(x)[1 + 0:(md - 1) * (dim(x)[1] + 1)]
nms <- dimnames(x)
if (is.list(nms) && !any(sapply(nms, is.null)) &&
all(nms[[1]][1:md] == nms[[2]][1:md]))
names(y) <- nms[[1]][1:md]
return(y)
}
... the rest as in the original function. Cheers, Jonathan.
Jonathan Rougier Science Laboratories
Department of Mathematical Sciences South Road
University of Durham Durham DH1 3LE
"[B]egin upon the precept ... that the things we see are to be
weighed in the scale with what we know" (Meredith, 1879, The Egoist)
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
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