R-alpha: cbind/memory-bug, (was Re: contr.helmert bug)

[Peter Dalgaard BSA]

Thomas Lumley <thomas@biostat.washington.edu> writes:

> I have a probably related problem. Sporadically, an attempt to do
> 
> a[,1,1,drop=F]
> 
> or similar subsetting on a 3-d matrix causes a segfault at line 83 of
> attrib.c.  In a previous version this happened reliably when dimensions
> were lost from multi-d arrays and was due to incorrect handling of the
> dimnames attributes which crashed attrib.c at that point when the dimnames
> were accessed.
> 
> Is the same sort of thing happening again?

Not at all unlikely. As far as I can see, this doesn't really have
anything to do with contr.helmert, but with cbind, dimnames, and
garbage collection. Contr.helmert only comes in due to the fact that
it provokes a garbage collection at a critical time. Your examples
don't involve the garbage collector, but it might still tickle the
same bug...

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907
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