On Wed, Jan 14, 2015 at 6:39 PM, Long Do Cao <docao@vega.ess.sci.osaka-u.ac.jp> wrote:

Hi all yt-users,

I'm running into a simple problem I think, but can't find the correct documentation. 

I want to make a slice plot of dark matter density with velocity vectors overlaid, using Gadget HDF5 data. I have uploaded my script here :

http://paste.yt-project.org/show/5347/

Hi Long,

This is a bit confusing in our API, and we should probably make an effort to improve our naming here, but the velocity callback ('annotate_velocity') is really the *gas* velocity callback.  It's not working in your case because you do not have any gas in your simulation.

Instead, you should call the quiver callback ('annotate_quiver'), and specify the deposited dark matter velocity fields as your field_x and field_y:

http://yt-project.org/docs/dev/reference/api/generated/yt.visualization.plot_modifications.QuiverCallback.html?highlight=quivercallback

Hope that helps, please let us know if you have any additional questions.

-Nathan

 

The slice plot works fine. However, I got an error message for the velocity overlay:

http://paste.yt-project.org/show/5349/

The bottom line is the following :

YTFieldNotFound: Could not find field '('all', 'velocity_x')' in snapshot_000.

The error is pretty obvious, I think YT is looking for the default field, whereas it should look for a deposit of the dark matter data. Somehow I should specify that yt should look for this deposit, but I don't know how ?

Thank you by advance for your help,

Long

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Long DO CAO (Office F617)

Office phone: +81 6-6850-5482

Osaka University, Graduate School of Science

Department of Earth and Space Science

1-1 Machikaneyama-cho

Toyonaka, Osaka, 560-0043, Japan

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