<html>#2516: Different simulation result with different number of cores setting
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<tr><td style='text-align:right'> Reporter:</td><td></td></tr>
<tr><td style='text-align:right'> Status:</td><td>open</td></tr>
<tr><td style='text-align:right'>Milestone:</td><td></td></tr>
<tr><td style='text-align:right'> Version:</td><td>ET_2019_10</td></tr>
<tr><td style='text-align:right'> Type:</td><td>bug</td></tr>
<tr><td style='text-align:right'> Priority:</td><td>major</td></tr>
<tr><td style='text-align:right'>Component:</td><td></td></tr>
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<p>Comment (by Roland Haas):</p>
<p>Unfortunately running twice with the same settings and getting the same result does not mean that the result does not depend on the order of operations in OpenMP. What it shows is only that that OpenMP choose the same order both times. You would have to check that you get the same result if you run with 1 OpenMP thread than you get with 2, 3, 4 etc. (It’s essentially the difference between deterministic but unpredictable and truly random).</p>
<p>To be clear: there is no checkpoint / recovery cycle in any of your runs?</p>
<p>Since you are looking at timeseries data in mp_psi4: do you observe all data to be off or is it only individual timesteps that are off?</p>
<p>You may want to check the actual grid data (eg ask for 3d output and compare the values in the output files) rather than the multipole output to see if the issue is in the evolution or in the analysis (Multipole itself, or the interpolators).</p>
<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2516/different-simulation-result-with-different'>https://bitbucket.org/einsteintoolkit/tickets/issues/2516/different-simulation-result-with-different</a></p>
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