[Rd] Windows crash in confint() with nls fit (PR#8428)

[bolker@zoo.ufl.edu]

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