<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Hi Axel,</div><div><br></div><div>First, I presume you are referring to the new unit system functionality in the development branch of yt, correct?</div><div><br></div><div>Currently in yt, "mol" is treated as "dimensionless" and we do not have units of candela. I recognize this is different from the SI standard, which has them as base units as you mentioned, and actually treats angles as dimensionless.</div><div><br></div><div>There are a couple of things going on here:</div><div><br></div><div>1. Angles are given a dimension since they have an important role in the areas of science for which yt was originally tailored to, and it helps things from a design perspective to distinguish them from dimensionless units.</div><div><br></div><div>2. The reason for the variance with the SI standard regarding mol and candela is somewhat historical as well; yt originally worked only in CGS units and even now assumes those as a default units base. The support for different unit systems is new. The fact that we treat mol as dimensionless and do not have candela is simply because a use case requiring otherwise has not presented itself yet.</div><div><br></div><div>Do you have an application of yt that requires a closer adherence to the SI standard? If so, we'd be willing to look into making some changes along these lines.</div><div><br></div><div>Best,</div><div><br></div><div>John</div><div><br><div><br><div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><span style="background-color: rgba(255, 255, 255, 0);">================================</span></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><span style="background-color: rgba(255, 255, 255, 0);">John ZuHone, Chandra/ACIS Operations<span class="Apple-tab-span" style="white-space: pre;"> </span></span></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><span style="background-color: rgba(255, 255, 255, 0);">Harvard-Smithsonian Center for Astrophysics<br class=""><br class=""></span></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><font color="#000000"><span style="background-color: rgba(255, 255, 255, 0);"><a dir="ltr" href="x-apple-data-detectors://0" x-apple-data-detectors="true" x-apple-data-detectors-type="address" x-apple-data-detectors-result="0">60 Garden St.</a>, MS-67 (w) <a dir="ltr" href="tel:617-496-1816" x-apple-data-detectors="true" x-apple-data-detectors-type="telephone" x-apple-data-detectors-result="1/0">617-496-1816</a><br class=""><a dir="ltr" href="x-apple-data-detectors://1/1" x-apple-data-detectors="true" x-apple-data-detectors-type="address" x-apple-data-detectors-result="1/1">Cambridge, MA 02138</a>. (m) <a dir="ltr" href="tel:781-708-5004" x-apple-data-detectors="true" x-apple-data-detectors-type="telephone" x-apple-data-detectors-result="1/2">781-708-5004</a></span></font></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><span style="background-color: rgba(255, 255, 255, 0);"><br class=""></span></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><font color="#000000"><span style="background-color: rgba(255, 255, 255, 0);"><a href="mailto:john.zuhone@cfa.harvard.edu" class="">john.zuhone@cfa.harvard.edu</a><br class=""><a dir="ltr" href="http://hea-www.cfa.harvard.edu/~jzuhone" x-apple-data-detectors="true" x-apple-data-detectors-type="link" x-apple-data-detectors-result="3">http://hea-www.cfa.harvard.edu/~jzuhone</a><br class="">================================</span></font><br class=""></div></div></div></div><div><br>On May 31, 2016, at 9:15 AM, Huebl, Axel <<a href="mailto:a.huebl@hzdr.de">a.huebl@hzdr.de</a>> wrote:<br><br></div><blockquote type="cite"><div><span>Dear yt-Developers,</span><br><span></span><br><span>we found today that the UnitSytem in YTEP-0028 has only 4 (MKS: 5) base</span><br><span>units + the angular measure.</span><br><span></span><br><span>This is a bit confusing since the SI unit system has seven base units,</span><br><span>further including mol (amount of substance) and candela (luminous</span><br><span>intensity), which are not available.</span><br><span></span><br><span>Is this intentional?</span><br><span></span><br><span></span><br><span>Best,</span><br><span>Axel</span><br><span></span><br><span>-- </span><br><span></span><br><span>Axel Huebl</span><br><span>Phone +49 351 260 3582</span><br><span><a href="https://www.hzdr.de/crp">https://www.hzdr.de/crp</a></span><br><span>Computational Radiation Physics</span><br><span>Laser Particle Acceleration Division</span><br><span>Helmholtz-Zentrum Dresden - Rossendorf e.V.</span><br><span></span><br><span>Bautzner Landstrasse 400, 01328 Dresden</span><br><span>POB 510119, D-01314 Dresden</span><br><span>Vorstand: Prof. Dr.Dr.h.c. R. Sauerbrey</span><br><span> Prof. Dr.Dr.h.c. P. Joehnk</span><br><span>VR 1693 beim Amtsgericht Dresden</span><br><span></span><br></div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>yt-dev mailing list</span><br><span><a href="mailto:yt-dev@lists.spacepope.org">yt-dev@lists.spacepope.org</a></span><br><span><a href="http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org">http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org</a></span><br></div></blockquote></body></html>