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Subject: Re: [OMPI users] Memory question and possible bug in 64bit addressing under Leopard!
From: Brian Barrett (brbarret_at_[hidden])
Date: 2008-04-25 16:10:57


On Apr 25, 2008, at 2:06 PM, Gregory John Orris wrote:

> produces a core dump on a machine with 12Gb of RAM.
>
> and the error message
>
> mpiexec noticed that job rank 0 with PID 75545 on node mymachine.com
> exited on signal 4 (Illegal instruction).
>
> However, substituting in
>
> float *X = new float[n];
> for
> float X[n];
>
> Succeeds!

You're running off the end of the stack, because of the large amount
of data you're trying to put there. OS X by default has a tiny stack
size, so codes that run on Linux (which defaults to a much larger
stack size) sometimes show this problem. Your best bets are either to
increase the max stack size or (more portably) just allocate
everything on the heap with malloc/new.

Hope this helps,

Brian

-- 
   Brian Barrett
   Open MPI developer
   http://www.open-mpi.org/