Hi Camryn, The two PNGs you shared actually appear identical to me. Also, it would help to know which version of yt you are using. Best, John Z On Jun 18 2020, at 5:04 pm, clp3ef@virginia.edu wrote:

Hi, I'm a new user of yt and have inherited some old code and data that was written in 2016 (original script and data: http://paste.yt-project.org/show/234/, http://use.yt/upload/6961a33c, http://use.yt/upload/b08c0345). The goal of the code was to produce projection plots of the density of tracer particles (notated by negative mass) which follow the ISM of simulated galaxies in groups. I believe it used to work, and produced a projection plot of the density of the tracer particles, called passivecic_field (https://i.imgur.com/woxJfm5.png). When I try to run the code now (using yt 3.60), I get the error KeyError: "No field named ('passive_part', 'passive_mass')".

I attempted to fix the issue by changing 'passive_mass' to 'particle_mass' in the definition of passivecic_field, and changing the filter so it accepts positive rather than negative mass particles, since passive_mass was just a negative scalar multiple of particle mass (new script: http://paste.yt-project.org/show/235/). This allows the code to run, but outputs the plot shown in http://use.yt/upload/0ecc9669, which shows few of the details of the original plot (especially the galaxy tails, which are what I am interested in). Do you know what might be causing the KeyError when passive_mass is used, and why the plot for particle_mass would have so much less detail?

Thanks, Camryn P. _______________________________________________ yt-users mailing list -- yt-users@python.org To unsubscribe send an email to yt-users-leave@python.org https://mail.python.org/mailman3/lists/yt-users.python.org/ Member address: jzuhone@gmail.com