[R-SIG-Mac] Segfault with rWishart in R 2.15.1

[peter dalgaard]

On Jul 4, 2012, at 03:12 , Michael Braun wrote:

> I just upgraded to R 2.15.1, and I am getting a segmentation fault when using the rWishart function (from the stats package) to sample moderately-size matrices.
> 
> Here is the output when I run R within gdb.  720 appears to be the dimensionality cut-off.  Anything smaller works fine.  Anything larger crashes.
> 
>> x=rWishart(1,700,diag(700)) // this works
>> x=rWishart(1,720,diag(720))
> Error: C stack usage is too close to the limit
>> x=rWishart(1,722,diag(722))
> 

That'll be due to allocating memory off the C stack with alloca(). Please file a bug report on this (nothing to do with Mac, much less with the age of your computer).

In a tight spot, you can run R from the terminal after raising the C stack limit with, say, "ulimit -s 32768", but of course the trouble returns at twice the matrix size. 

Notice that there are really two issues here. One is that the R_CheckStack() safeguards are failing. The other is why we're using stack allocation in the first place.  

-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com