Hi all, Thank you for all the suggestions! I decided to try something similar to Sam's shock identification first. Here is a problem I encountered: I tried to define a field of the temperature gradient like gradPressureX, but I got an error message: ... new_field[1:-1,1:-1,1:-1] = data["Temperature"][sl_right,1:-1,1:-1]/ds ValueError: could not broadcast input array from shape (62,62,64) into shape (62,62,62) I then tried to re-define gradPressureX by copying the original definition and giving it a different name, and I got the same error. The original gradPressureX works fine. Is it because I did not load some specific module or something? I am using HydroMethod = 2. Thank you! Yuan On Wed, Jun 24, 2015 at 5:47 AM, Christine Simpson < csimpson@astro.columbia.edu> wrote:

Hi Yuan,

I don’t have any advice to give on shock-finding in yt or Enzo, but I thought I’d point out this paper:

http://arxiv.org/abs/1407.4117

You might find Section 5 interesting. Basically, a common assumption of shock finders is to filter using the dot product of the temperature and entropy gradients. When you do this, the computed dissipated energy can be sensitive to your assumptions for the other jump requirements, and depending on what you assume, can identify spurious shocks. This paper instead of using the entropy gradient, uses the density gradient, and gives somewhat different results. More knowledgable people than me can probably give you better advice, but I thought you might find this interesting, especially if you’re going to write something yourself.

Christine

On Jun 23, 2015, at 5:51 PM, Yuan Li

wrote: Dear all,

I am trying to figure out a way to mask out cells that contain shocks. One way I can think of is to create a derived field by identifying shocks. It seems that there are different ways of finding shocks: Enzo has a refinement criterion (refine by shocks) and there is also shock finding written by Sam.

Has anybody tried to find shocks using yt? I would appreciate it if you would like to share your code/experience/advice. Thank you!

Yuan _______________________________________________ yt-users mailing list yt-users@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org

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