Bug in predict.lm?
The same problem appears on a 64-bit linux:
platform x86_64-pc-linux-gnu
arch x86_64
os linux-gnu
system x86_64, linux-gnu
status
major 3
minor 0.2
year 2013
month 09
day 25
svn rev 63987
language R
version.string R version 3.0.2 (2013-09-25)
nickname Frisbee Sailing
After dputting the predict.lm function (traceback etc. did not give a hint
on the source of the error message) I could locate the invalid call at
around the 70-80th rows of the function:
...
if (type != "terms") {
if (p > 0) {
XRinv <- if (missing(newdata) && is.null(w))
qr.Q(qr.lm(object))[, p1, drop = FALSE]
else X[, piv] %*% qr.solve(qr.R(qr.lm(object))[p1,
p1])
ip <- drop(XRinv^2 %*% rep(res.var, p))
} else ip <- rep(0, n)
}
...
Here ...&& is.null(w)... causes the troubles.
Bert Gunter <gunter.berton <at> gene.com> writes:
Yes, I realize that it is more likely a misunderstanding on my part. Suitable humility will be tendered if this is pointed out. The claimed "bug" is that predict.lm throws an error when the scale argument is specified with interval = "conf" (and in some other cases):
z <- lm(rnorm(10)~I(1:10))
predict(z,int="conf",scale=1)
Error in predict.lm(z, int = "conf", scale = 1) : object 'w' not found R version 3.0.2 (2013-09-25) Platform: i386-w64-mingw32/i386 (32-bit) Cheers, Bert
I do not see this (see below). Maybe traceback() or options(recover=browser) to get to the bottom??
z <- lm(rnorm(10)~I(1:10)) predict(z,int="conf",scale=1)
fit lwr upr 1 0.02491723 -1.1270591 1.1768935 2 0.06402057 -0.9129873 1.0410284 3 0.10312392 -0.7185606 0.9248085 4 0.14222726 -0.5569958 0.8414504 5 0.18133060 -0.4477852 0.8104464 6 0.22043395 -0.4086818 0.8495497 7 0.25953729 -0.4396858 0.9587604 8 0.29864063 -0.5230439 1.1203252 9 0.33774398 -0.6392639 1.3147518 10 0.37684732 -0.7751290 1.5288236
version
_ platform x86_64-apple-darwin10.8.0 arch x86_64 os darwin10.8.0 system x86_64, darwin10.8.0 status major 3 minor 0.2 year 2013 month 09 day 25 svn rev 63987 language R version.string R version 3.0.2 (2013-09-25) nickname Frisbee Sailing
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