Full_Name: Ben Bolker
Version: 2.2.1
OS: Windows XP and 2000
Submission from: (NULL) (128.227.60.124)
The following code, using confint() to try
to get confidence intervals on an nls object
that has been fitted with algorithm="port"
reliably crashes R 2.2.0 and 2.2.1 with the
latest version of MASS on a Windows 2000 and
a Windows XP machine here. I *think* earlier
versions of MASS may not have crashed, but
I have now updated the versions on most of
my machines and don't have a test version handy.
On XP, I get an error-report-do-you-want-
to-send-this-to-Microsoft dialog box. On 2000
I get a "Rgui has generated errors ..." dialog box.
I can get this far:
debug: profiledModel <- .Call("nls_iter", fittedModel, ctrl, trace,
PACKAGE = "stats")
Browse[1]> where
where 1: prof$getProfile()
where 2: profile.nls(object, which = parm, alphamax = (1 - level)/4)
where 3: profile(object, which = parm, alphamax = (1 - level)/4)
where 4: confint.nls(n1)
where 5: confint(n1)
I'm not set up to debug compiled code on Windows, and I haven't
been able to reproduce the problem on Linux.
set.seed(1001)
x = runif(200)
a =1
b = 1
c = -0.1
y = a+b*x+c*x^2+rnorm(200,sd=0.05)
plot(x,y)
curve(a+b*x+c*x^2,add=TRUE)
n1 = nls(y~a+b*x+c*I(x^2),start=c(a=1,b=1,c=0.1),algorithm="port")
confint(n1) ## boom
N.B.: It only crashes if algorithm="port" is specified.
## [1] "Windows 2000 Professional (build 2195) Service Pack 4.0"
##
## > R.version
## _
## platform i386-pc-mingw32
## arch i386
## os mingw32
## system i386, mingw32
## status
## major 2
## minor 2.0
## year 2005
## month 10
## day 06
## svn rev 35749
## language R
##
## MASS
##
## Version: 7.2-23
## Date: 2005-12-08
##
##
## "Windows XP Professional (build 2600) Service Pack 2.0"
## _
##platform i386-pc-mingw32
##arch i386
##os mingw32
##system i386, mingw32
##status
##major 2
##minor 2.0
##year 2005
##month 10
##day 06
##svn rev 35749
##language R
##
##Version: 7.2-23
##Date: 2005-12-08 ## CRASH
##> R.version
## _
##platform i386-pc-mingw32
##arch i386
##os mingw32
##system i386, mingw32
##status
##major 2
##minor 2.1
##year 2005
##month 12
##day 20
##svn rev 36812
##language R
## CRASH
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