<html>#2723: No boundary conditions registered for variables in group LEANBSSNMOL
<table style='border-spacing: 1ex 0pt; '>
<tr><td style='text-align:right'> Reporter:</td><td>Vikram Manikantan</td></tr>
<tr><td style='text-align:right'> Status:</td><td>new</td></tr>
<tr><td style='text-align:right'>Milestone:</td><td>ET_2023_05</td></tr>
<tr><td style='text-align:right'> Version:</td><td>ET_2022_11</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>
</table>
<p>Comment (by Samuel Cupp):</p>
<p>I’ve never used this thorn, but I can hazard a guess. On the master branch, the function <code>LeanBSSN_Boundaries</code> doesn’t run until</p>
<div class="codehilite"><pre><span></span><span>schedule LeanBSSN_Boundaries in MoL_PostStep</span>
<span>{</span>
<span> LANG: Fortran</span>
<span> OPTIONS: LEVEL</span>
<span> SYNC: ADMBase::lapse</span>
<span> SYNC: ADMBase::shift</span>
<span> SYNC: LeanBSSNMoL::conf_fac</span>
<span> SYNC: LeanBSSNMoL::hmetric</span>
<span> SYNC: LeanBSSNMoL::hcurv</span>
<span> SYNC: LeanBSSNMoL::trk</span>
<span> SYNC: LeanBSSNMoL::gammat</span>
<span>} "MoL boundary enforcement"</span>
</pre></div>
<p>In the old approach, boundary conditions and ghost zone synchronization were completely independent. Now, we simply do both at the same time. Hence, scheduling like</p>
<div class="codehilite"><pre><span></span><span>schedule LeanBSSN_adm2bssn at CCTK_INITIAL after ADMBase_PostInitial</span>
<span>{</span>
<span> LANG: Fortran</span>
<span> OPTIONS: Local</span>
<span> SYNC: gammat</span>
<span>} "Convert initial data into BSSN variables"</span>
</pre></div>
<p>will naturally trigger warnings if there are no BCs yet. Additionally, the old method didn’t make it clear that the ApplyBCs scheduled at CCTK_INITIAL was an empty call that did nothing. Since the registered BCs look to be <code>none</code>, it doesn't actually matter. I thought this was resolved in <a data-is-external-link="true" href="https://bitbucket.org/einsteintoolkit/tickets/issues/2723/no-boundary-conditions-registered-for" rel="nofollow">Issue #2648</a>. However, the changes aren’t in master. This ticket changed</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">OP
<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2723/no-boundary-conditions-registered-for'>https://bitbucket.org/einsteintoolkit/tickets/issues/2723/no-boundary-conditions-registered-for</a></p>
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