[Rd] qr.qy and qr.qty give an error message when y is integer and LAPACK=TRUE
Berend Hasselman
bhh at xs4all.nl
Mon Dec 3 15:25:21 CET 2012
With this example
set.seed(123)
A <- matrix(runif(40), nrow = 8)
y <- 1:nrow(A)
A.laqr <- qr(A, LAPACK=TRUE)
both qr.qy(A.laqr,y) and qr.qty(A.laqr,y) give the respective error messages
Error in qr.qy(A.laqr, y) : 'b' must be a numeric matrix
Error in qr.qty(A.laqr, y) : 'b' must be a numeric matrix
However when Lapack is not used as in
A.liqr <- qr(A, LAPACK=FALSE)
qr.qy(A.liqr,y) and qr.qty(A.liqr,y) don't issue error messages.
Looking at the source of qr.qy and qr.qty in https://svn.r-project.org/R/trunk/src/library/base/R/qr.R
I see that in the case of Lapack the storage.mode of y is not set to "double" (in contrast to when Linpack QR has been used).
I assume that the error issued when LAPACK=TRUE is not intended.
Berend
Suggested code change in qr.qy
Replace
if(!is.null(a) && is.logical(a) && a)
return(.Call("qr_qy_real", qr, as.matrix(y), 0, PACKAGE = "base"))
with
if(!is.null(a) && is.logical(a) && a) {
storage.mode(y) <- "double"
return(.Call("qr_qy_real", qr, as.matrix(y), 0, PACKAGE = "base"))
}
and a similar change in qr.qty
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