<html>#2368: Instabilities with Summation by Parts thorn 4th order operator
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<tr><td style='text-align:right'> Reporter:</td><td>Miguel Zilhão</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></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 Miguel Zilhão):</p>
<p>Thanks for looking into this. Indeed, I can confirm that setting SummationByParts::operator_type = "Minimal Bandwidth" with the 4th order accurate 2nd derivative operator seems to lead to a stable evolution. Should this maybe be the default choice?</p>
<p>With the optimal stencil, the instabilities seem to grow from the boundary. Could this somehow be due to a mismatch between the truncation error in the bulk and boundary regions?</p>
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<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2368/instabilities-with-summation-by-parts'>https://bitbucket.org/einsteintoolkit/tickets/issues/2368/instabilities-with-summation-by-parts</a></p>
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