[Rd] Fwd: segfault

[Deepayan Sarkar]

On Monday 29 August 2005 03:35, Prof Brian Ripley wrote:
> It does not crash for me on either Windows or Linux, but it does take a
> long time and the plot is a mess, so there does seem to be a
> lattice-related problem (maybe a usage one).

It is improper (or at least unanticipated) usage. The example cited does not 
crash X11 on GNU/Linux for me, but the following does:

wireframe(F ~ x * p, bt, groups = factor(p), shade=TRUE) 

This involves some C code in lattice, which could well be the culprit. I'll 
clarify the documentation, but I'm not sure how easy it would be to catch the 
bug.

Deepayan

> However, I think the crash is a Mac (presumably quartz()) problem.
>
> On Mon, 29 Aug 2005, stefano iacus wrote:
> > This segfaults on OS X (10.4) on both X11 and quartz devices.
> > Seems a problem with lattice but I cannot test on other platforms
> > stefano
> >
> > Begin forwarded message:
> >> From: "G. Sawitzki" <gs at statlab.uni-heidelberg.de>
> >> Date: 28 agosto 2005 14:11:18 GMT+02:00
> >> To: jago at mclink.it
> >>
> >>
> >> Dear Stefano,
> >>
> >>  this small exaple leads to a crash of R. I did not try it on
> >> versions other than the Mac version. So I am sending it to you
> >> directly. If it is a littice problem, could you pass it to Deepayan
> >> Sarkar? Thank you.
> >>
> >>   g.
> >>
> >> ==
> >> #pbinom
> >> library(grid)
> >> library(lattice)
> >>
> >> n<-20
> >> psteps<-50
> >> binomtable<- function (n,psteps){
> >> x<-(0:(10*n))/10
> >> p<- (0:psteps)/psteps
> >> dd<-expand.grid(x=x,p=p)
> >> dd$F<- pbinom(dd$x,n,dd$p)
> >> dd$x0<-trunc(dd$x)
> >> dd
> >> }
> >>
> >> bt<-binomtable(n=5,psteps=100)
> >> bt[bt$x-bt$x0>=0.9,]$F<-NA
> >> wireframe(bt$F~bt$x*bt$p,bt,groups=bt$x0,shade=TRUE) # leads to R
> >> crash
> >> #wireframe(bt$F~bt$x*bt$p,bt,shade=TRUE) #ok