<div dir="ltr"><div><div>If I recall correctly. The RAMSES frontend has not been tested much with non-cosmological runs as of right not (correct me if I am wrong).<br><br></div>I haven't got any non-comsological datasets to test with right now.. likewise all of my cosmological runs have boxlen = 1.0. I think I know where to get hold of a non-cosmological run and when I get the chance I will load it up with pymses and see what is needed to be changed to work with non-cosmological models.<br><br></div>Ben<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jun 4, 2015 at 7:18 PM, Nathan Goldbaum <span dir="ltr"><<a href="mailto:nathan12343@gmail.com" target="_blank">nathan12343@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">This was last touched back in December:<div><br></div><div><a href="https://bitbucket.org/yt_analysis/yt/pull-request/1335/ramses-unit-conversions/diff" target="_blank">https://bitbucket.org/yt_analysis/yt/pull-request/1335/ramses-unit-conversions/diff</a><br></div><div><a href="https://bitbucket.org/yt_analysis/yt/issue/939/units-error-in-ramses-frontend" target="_blank">https://bitbucket.org/yt_analysis/yt/issue/939/units-error-in-ramses-frontend</a><br></div><div><br></div><div>when I updated this, I attempted to set the units in exactly the same way as pymses. Unfortunately since I'm not a ramses user and don't have access to a diversity of test datasets, it's hard to get this exactly right in all cases.</div><div><br></div><div>Is your dataset cosmological? I wouldn't be surprised if there are subtle differences in the way units are set up for comoving and non-comoving simulations.</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Thu, Jun 4, 2015 at 2:59 PM, Desika Narayanan <span dir="ltr"><<a href="mailto:dnarayan@haverford.edu" target="_blank">dnarayan@haverford.edu</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr">Hey YT-dev,<div><br></div><div>I've discovered something that I think could maybe be a bug (though maybe not) in the Ramses front end but am unsure about the motivation behind the code so thought I'd check in and try to learn a bit.</div><div><br></div><div>In frontends/ramses/data_structures.py, I think the length_unit is set to be the length_unit that comes from the info_xxx.txt file multiplied by the box length. For the example yt data sets, this doesn't impact anything because the box lengths are unity.</div><div><br></div><div>In examining some Agora snapshots, however the box lengths are not unity - one that I'm looking at for example has a boxlen of 600. This results in length units that aren't similar to what the info_xxx.txt file says, and more dramatically, mass units that are very different. For example, in one such snapshot, I read from the info file:</div><div><br></div><div>
<p>boxlen = 0.600000000000000E+03<br>time = 0.500035810875167E+00<br>aexp = 0.100000000000000E+01<br>H0 = 0.100000000000000E+01<br>omega_m = 0.100000000000000E+01<br>omega_l = 0.000000000000000E+00<br>omega_k = 0.000000000000000E+00<br>omega_b = 0.000000000000000E+00<br>unit_l = 0.308656802500000E+22<br>unit_d = 0.157339152800000E-25<br>unit_t = 0.308687241173998E+17</p><p>but if I load this snapshot in yt, I get:</p><p><span>>In [2]: </span>print ds.mass_unit<br>9.9935115109e+46 g</p><p><span>>In [3]: </span>print ds.mass_unit.in_units("Msun")<br>5.02586592269e+13 Msun</p><p>><span>In [4]: </span>print ds.length_unit<br>1.851940815e+24 cm</p><p>which consequently results in derived quantities from the simulation (like stellar mass) that are totally off (by a factor boxlen**3).</p><p>So, I'm writing (as a total Ramses novice) to try to understand the motivation behind multiplying the length unit by the boxlen in the frontend, and if I should be accounting for this factor of boxlen**3 in my analysis, or if this is a bona fide bug.</p><p>Thanks, <br>-desika</p><p>ps I updated this morning:</p><p>thundersnow:yt desika$ hg id<br>8d3663ac217d+ (yt) tip</p></div></div>
<br></div></div>_______________________________________________<br>
yt-dev mailing list<br>
<a href="mailto:yt-dev@lists.spacepope.org" target="_blank">yt-dev@lists.spacepope.org</a><br>
<a href="http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org" target="_blank">http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org</a><br>
<br></blockquote></div><br></div>
<br>_______________________________________________<br>
yt-dev mailing list<br>
<a href="mailto:yt-dev@lists.spacepope.org">yt-dev@lists.spacepope.org</a><br>
<a href="http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org" target="_blank">http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org</a><br>
<br></blockquote></div><br></div>