I *do* see the same phenomenon that Bert describes and the code of
predict.lm()
*does* appear to contain a bug. There is a line:
XRinv <- if (missing(newdata) && is.null(w))
But "w" gets assigned (as object$weights) only if (is.null(scale)).
If that assignment is moved outside of the applicable "if field" (e.g.
and is put
just after the line:
if (se.fit || interval != "none") {
then predict.lm() throws no error.
> sessionInfo()
R version 3.0.2 Patched (2013-09-26 r64005)
Platform: x86_64-unknown-linux-gnu (64-bit)
locale:
[1] C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] fortunes_1.5-0 misc_0.0-15
loaded via a namespace (and not attached):
[1] tools_3.0.2
The operative difference between my set-up and Chuck's is that I am using
version 3.0.2 Patched. So I am very puzzled as to why Chuck does *not* get
an error thrown!
BTW traceback() was not helpful:
> predict(z,int="conf",scale=1)
Error in predict.lm(z, int = "conf", scale = 1) : object 'w' not found
> traceback()
2: predict.lm(z, int = "conf", scale = 1)
1: predict(z, int = "conf", scale = 1)
cheers,
Rolf
On 11/16/13 10:55, Charles Berry wrote:
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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