[MITgcm-support] shared memory mac

[Ed Hill]

On Tue, 2005-12-13 at 12:30 -0800, Dmitri Leonov wrote:
> Hi Nicolas,
> 
> > But to me, OpenMp is a working option on the Mac.
> >
> Did it work?
> 
> I used the modifications described at
> http://mitgcm.org/pipermail/mitgcm-support/2003-October/001753.html
> 
> One of the errors was
> 
> (PID.TID 0000.0001) *** ERROR *** MDSWRITEFIELD: Stopping because you 
> are using threads

Hi Dmitri,

I think you're getting the above error because you're trying to use the
globalFiles option (see the main "data" namelist file) in conjunction
with both threads (OpenMP) and the MDSIO package -- which is not a
supported way of doing things.

So you might want to think about using MPI instead of OpenMP on your
dual-processor Mac.  There are two reasons: (1) the MPI mode of
operation is much better tested within MITgcm than the multi-threaded
mode and (2) most MPI implementations will do a decent job of handling
the case of all-local communication so, in theory at least, you
shouldn't get a big performance hit for using MPI instead of
OpenMP/threads.

Ed

-- 
Edward H. Hill III, PhD
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