<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 7, 2014 at 7:45 PM, Matthew Turk <span dir="ltr"><<a href="mailto:matthewturk@gmail.com" target="_blank">matthewturk@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class=""><div class="h5">On Tue, Oct 7, 2014 at 7:55 PM, Andrew Myers <<a href="mailto:atmyers2@gmail.com">atmyers2@gmail.com</a>> wrote:<br>
> Hi Folks,<br>
><br>
> I'm trying to understand how the particle deposition fields work for<br>
> grid-based codes. Specifically, how does yt handle particles that are close<br>
> to the grid boundaries, so that the CIC interpolation stencil involves cells<br>
> on grid(s) other than the one that contains the particle position?. Like,<br>
> say I did:<br>
><br>
> import yt<br>
> ds = yt.load(fn)<br>
> g = ds.index.grids[0]<br>
> print g['deposit', 'all_cic']<br>
><br>
> How does yt handle the fact that particles other than those living on "g"<br>
> can contribute to the total CIC density? Does it grab a layer of "ghost<br>
> particles" somehow? I can't seem to find where that happens.<br>
><br>
> Sorry if I'm just missing something obvious here...<br></div></div></blockquote><div><br></div><div><div>Andrew's original e-mail prompted me to make the following notebook, which might prove useful for constructing a unit test:</div><div><br></div><div><a href="http://nbviewer.ipython.org/gist/ngoldbaum/eb40dfe74cd58a4e16ba">http://nbviewer.ipython.org/gist/ngoldbaum/eb40dfe74cd58a4e16ba</a></div></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div class=""><div class="h5">
<br>
</div></div>It doesn't, and you're not.  This is something it should do, but does<br>
not currently.  If you're using a "smoothing" operation, it will, as<br>
then it handles non-local particles, but deposit operations don't do<br>
ghost zones.<br></blockquote><div><br></div><div>Smoothing is also only implemented for octrees.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<br>
This is something we should fix, and that we probably could by simply<br>
making all the CIC fields ValidateSpatial(1).  Can you give that a<br>
shot?<br></blockquote><div><br></div><div>Will this have interactions with <a href="https://trello.com/c/SFuSSoIo">https://trello.com/c/SFuSSoIo</a> ?</div><div><br></div><div>I think the answer is no, since we're querying particle fields and selection doesn't require cascading interpolation, but I just want to double-check.</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<br>
><br>
> Best,<br>
> Andrew<br>
><br>
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