[Rd] unstability when using isoreg() function (PR#6494)

[dmurdoch at pair.com]

On Wed, 28 Jan 2004 17:31:27 +0100 (CET), you wrote:

>Full_Name: Petr Klasterecky
>Version: 1.8.1
>OS: Windows XP, Linux
>Submission from: (NULL) (195.113.27.212)
>
>
>The isoreg() function causes R to crash when called repeatedly. Consider the
>following simple script:
>
>{
>library(modreg)
>N <- 10
>x <- rnorm(N)
>print("Original x values:")
>print(x)
>for(n in (1:N)){print(y <- isoreg(x[1:n])$yf)}
>} 

I get the crash reproducibly in r-devel after I put "set.seed(2)"
ahead of the sample code above.  (Of course, r-devel doesn't need the
library(modreg), but that doesn't affect the bug.)  Other seeds and
the code works without error.

I tried tracing into R_isoreg to try to spot the problem, but the
error occurs after it returns.  It has all the symptoms of some code
writing outside allocated bounds, but I couldn't see where that
happened.

Duncan Murdoch