<html>#2271: Problem with MPI process
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<tr><td style='text-align:right'> Reporter:</td><td></td></tr>
<tr><td style='text-align:right'> Status:</td><td>new</td></tr>
<tr><td style='text-align:right'>Milestone:</td><td></td></tr>
<tr><td style='text-align:right'> Version:</td><td></td></tr>
<tr><td style='text-align:right'> Type:</td><td>bug</td></tr>
<tr><td style='text-align:right'> Priority:</td><td>minor</td></tr>
<tr><td style='text-align:right'>Component:</td><td></td></tr>
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<p>Comment (by Roland Haas):</p>
<p>Yes, using <code>--procs=4 --num-threads=2</code> will work for you. For historial reasons <code>--procs</code> really means "number of cores to use". Simfactory has some idea of how many threads per MPI rank one is to use by default and currently, on a laptop that numbers "as many threads as the laptop has cores". simfactory will only create more than 1 MPI rank of more cores ("procs") than threads are requested. Using <code>--num-threads</code> explicitly tells simfactory how many threads to use per MPI rank. The number of MPI ranks used is then <code>procs / num-threads</code> ie 2 in your example with both <code>--procs</code> and <code>--num-threads</code> and likely 1 without <code>--num-threads</code> if you workstation has more than 4 cores.</p>
<p>To know for sure you would have to inspect your laptop's machine.ini file in <code>simfactory/mdb/machines/</code> (it will be named after the hostname of your laptop ie the name that <code>simfactory/bin/sim whoami</code> outputs).</p>
<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2271/problem-with-mpi-process'>https://bitbucket.org/einsteintoolkit/tickets/issues/2271/problem-with-mpi-process</a></p>
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