<html>#2648: Empty ApplyBCs call in LeanBSSNMoL
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<tr><td style='text-align:right'> Reporter:</td><td>Samuel Cupp</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>major</td></tr>
<tr><td style='text-align:right'>Component:</td><td>EinsteinToolkit thorn</td></tr>
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<p>Comment (by helvi witek):</p>
<blockquote>
<p>After ADM2BSSN one usually has to SYNC, extrapolate and apply symmetry boundary conditions (possibly in a very specific order) and the Gamma auxiliary variables of the BSSN system which involve derivatives so cannot be set in ghost zones and the boundary. Most others can be computed point by point, so that a missing SYNC (missing for sure it seems) will only show up a slight change in regions filled via prolongation (but not in inter-processor ghosts or in restriction target region).</p>
</blockquote>
<p>@Roland: Ok, Let me add the relevant part of schedule.ccl:</p>
<div class="codehilite"><pre><span></span><span class="n">schedule</span> <span class="n">LeanBSSN_adm2bssn</span> <span class="k">at</span> <span class="n">CCTK_INITIAL</span> <span class="k">after</span> <span class="n">ADMBase_PostInitial</span>
<span>{</span>
<span class="n">LANG</span><span class="p">:</span> <span class="k">Fortran</span>
<span class="k">OPTIONS</span><span class="p">:</span> <span class="k">Local</span>
<span class="n">SYNC</span><span class="p">:</span> <span class="n">gammat</span>
<span>}</span> <span class="ss">"Convert initial data into BSSN variables"</span>
<span class="n">schedule</span> <span class="k">GROUP</span> <span class="n">ApplyBCs</span> <span class="k">as</span> <span class="n">LeanBSSN_ApplyBCs</span> <span class="k">at</span> <span class="n">CCTK_INITIAL</span> <span class="k">after</span> <span class="n">LeanBSSN_adm2bssn</span>
<span>{</span>
<span>}</span> <span class="ss">"Apply boundary conditions"</span>
</pre></div>
<p></p>
<p>In Lean, we extrapolate gammat at the end of the routine “LeanBSSN_adm2bssn”, and sync as shown.</p>
<p>Our understanding was that “ApplyBCs” then applies the symmetry boundary conditions.</p>
<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2648/empty-applybcs-call-in-leanbssnmol'>https://bitbucket.org/einsteintoolkit/tickets/issues/2648/empty-applybcs-call-in-leanbssnmol</a></p>
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