<html>#2887: TwoPunctures does not support Slow-Start Lapse.
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<tr><td style='text-align:right'> Reporter:</td><td>Zach Etienne</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>enhancement</td></tr>
<tr><td style='text-align:right'> Priority:</td><td>major</td></tr>
<tr><td style='text-align:right'>Component:</td><td></td></tr>
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<p>Comment (by Roland Haas):</p>
<p>hmm, how about: <a data-is-external-link="true" href="https://bitbucket.org/einsteintoolkit/tickets/issues/2706/update-default-twopunctures-parameters-or?iframe=true&spa=0#comment-65802578" rel="nofollow">https://bitbucket.org/einsteintoolkit/tickets/issues/2706/update-default-twopunctures-parameters-or?iframe=true&spa=0#comment-65802578</a> </p>
<blockquote>
<p>The BBH gallery example has a rather unusual choice of initial lapse, setting it to the average value of 1 - m_i / (2r_i) for both punctures i. More typically the initial lapse is set to the “pre-collapsed” value of psi^{-2} which goes like 1 - M/r at large radii for total binary mass M. This is the same asymptotic behavior that the will lapse relax to, and so this choice results in less gauge dynamics than the “averaged lapse” value. TwoPunctures supports <code>initial_lapse = "psi^n"</code> and chooses a perfectly fine default value of <code>n=initial_lapse_psi_exponent=-2</code> .</p>
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<p>--<br/>
Ticket URL: <a href='https://bitbucket.org/einsteintoolkit/tickets/issues/2887/twopunctures-does-not-support-slow-start'>https://bitbucket.org/einsteintoolkit/tickets/issues/2887/twopunctures-does-not-support-slow-start</a></p>
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