<html>#2160: QuasiLocalMeasures qlm_spin doesn't work for spins not aligned along the z axis
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<tr><td style='text-align:right'> Reporter:</td><td></td></tr>
<tr><td style='text-align:right'> Status:</td><td>wontfix</td></tr>
<tr><td style='text-align:right'>Milestone:</td><td></td></tr>
<tr><td style='text-align:right'> Version:</td><td>development version</td></tr>
<tr><td style='text-align:right'> Type:</td><td>bug</td></tr>
<tr><td style='text-align:right'> Priority:</td><td>minor</td></tr>
<tr><td style='text-align:right'>Component:</td><td>EinsteinToolkit thorn</td></tr>
</table>
<p>Changes (by Roland Haas):</p>
<p><table>
<tr><td>status:</td><td>wontfix (was new)</td></tr>
</table></p>
<p>Einstein Toolkit version: <code>ET_2018_02</code>.</p>
<p>Parameter file: <code>qc0-mclachlan.par</code> in einsteinexamples with the additional parameter <code>TwoPunctures::par_S_plus [0] = +0.3</code></p>
<p>Problem: The diagnostic <code>qlm_spin[0]</code> returns a spin of 0, whereas the expected one should be 0.3.</p>
<p>If instead of <code>TwoPunctures::par_S_plus [1] = +0.3</code> one sets
<code>TwoPunctures::par_S_plus [2] = +0.3</code>, <code>qlm_spin[0]</code> is correctly
outputting 0.3</p>
<p>This happens because QuasiLocalMeasures finds in both cases the rotational Killing vector d/dphi (as seen setting <code>QuasiLocalMeasures::veryverbose = yes</code>), which is correct in the second case (when the axis aligned with the z-direction), but doesn't sound right when the rotation is with respect to the x-axis.</p>
<p>Changing <code>QuasiLocalMeasures::killing_vector_method</code> to <code>axial</code> or <code>gradient</code> does not change the outcome.</p>
<p>Best regards,
Gabriele</p>
<p><strong>Keyword:</strong> QuasiLocalMeasures</p>
<p>Comment (by Roland Haas):</p>
<p>Works as designed. This limit should be documented.</p>
<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2160/quasilocalmeasures-qlm_spin-doesnt-work'>https://bitbucket.org/einsteintoolkit/tickets/issues/2160/quasilocalmeasures-qlm_spin-doesnt-work</a></p>
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