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<div class="">On 26 Feb 2020, at 15:09, 刘昊阳 <<a href="mailto:liuhaoyang19@mails.ucas.edu.cn" class="">liuhaoyang19@mails.ucas.edu.cn</a>> wrote:</div>
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<div class="">Dear colleague:<br class="">
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I'm Liu Haoyang, a fresher of EinsteinToolkit from University of Chinese Academy of Science.<br class="">
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I found that some Thorn's documents in Thorn Guide lack detailed description about their variables' function, such as "Carpet" and "ReflectionSymmetry". And it seems that access to
<a href="https://carpetcode.org/" class="">https://carpetcode.org/</a> is restricted.<br class="">
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Is there any other material for such Thorns I can learn about? And how can I have access to the website of Carpet?<br class="">
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<div>Hi,</div>
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<div>The best place to look at an overview of the documentation is probably</div>
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<div><a href="https://einsteintoolkit.org/documentation/ThornGuide.php" class="">https://einsteintoolkit.org/documentation/ThornGuide.php</a></div>
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<div>It's true that the Carpet thorn doesn't have any documentation, but the Carpet
<i class="">arrangement</i><span style="font-style: normal;" class=""> does. This applies to the whole arrangement of Carpet thorns. You can read it here:</span></div>
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<div><a href="https://einsteintoolkit.org/arrangementguide/Carpet/documentation.html" class="">https://einsteintoolkit.org/arrangementguide/Carpet/documentation.html</a></div>
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<div class="">I'm not sure what happened to <a href="http://carpetcode.org" class="">
carpetcode.org</a>. Erik Schnetter is the original author of Carpet, and his website still has that link (<a href="https://www.perimeterinstitute.ca/personal/eschnetter/" class="">https://www.perimeterinstitute.ca/personal/eschnetter/</a>), so I assume the
website has gone down and is unnoticed. I will ask him in a separate thread.</div>
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<div class="">Yes, the symmetry thorns don't appear to be documented. </div>
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<div class="">Often, you can work out how to use a thorn by looking at the available parameters in params.ccl:</div>
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<div class=""><a href="https://bitbucket.org/cactuscode/cactusnumerical/src/master/ReflectionSymmetry/param.ccl" class="">https://bitbucket.org/cactuscode/cactusnumerical/src/master/ReflectionSymmetry/param.ccl</a></div>
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<div class="">That, at least, is less likely to be out of date than any documentation!</div>
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<div class="">The main idea, if you want to use reflection symmetry, is that you need to set up your domain, e.g. with CoordBase parameters, to contain only the portion you want to simulate. E.g. if you have a symmetry z -> -z, then you could set zmin = 0.
You then activate ReflectionSymmetry and set ReflectionSymmetry::reflection_z = "yes", ReflectionSymmetry::avoid_origin_z = "no" (the need for the latter is due to an unfortunate default, from what I remember).</div>
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-- <br class="">
Ian<b class=""><span class="Apple-converted-space"> </span></b>Hinder<br class="">
Research Software Engineer<br class="">
University of Manchester, UK</div>
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