<html>#2930: Bug in QuasiLocalMeasures
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<tr><td style='text-align:right'> Reporter:</td><td>Marco Brito</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>I found a bug in the QuasiLocalMeasures thorn, in the computation of the ADM momentum. In the source code file qlm_analyse.F90, in line 361 there is a plus sign instead of a minus sign, contradicting the ADM momentum formula: P^i_{ADM} = \frac{1}{8\pi}\lim_{r\to\infty} \oint_S (K^i_j - \delta^i_j K)dS^j [1]</p>
<p>As expected for slices where K \neq 0 one was getting a wrong result. The correction is easy, just replace the plus sign by a minus sign. You can find the corrected file in attachment.</p>
<p>[1] M. Alcubierre, Introduction to 3+1 Numerical Relativity, International Series of Monographs on Physics (Oxford University Press, Oxford, 2008).</p>
<p><table><tr><td>attachment:</td><td><a href="https://api.bitbucket.org/2.0/repositories/einsteintoolkit/tickets/issues/2930/attachments/qlm_analyse.F90">qlm_analyse.F90</a></td></tr>
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<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2930/bug-in-quasilocalmeasures'>https://bitbucket.org/einsteintoolkit/tickets/issues/2930/bug-in-quasilocalmeasures</a></p>
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