Hi Mike, This is a problem. The issue is actually that "data_source" is not the right argument, and gets passed as a field argument instead. If you set it to "source" this will fix the issue you're seeing. But, ugh, this is terrible, and I take responsibility. The kwargs argument is the issue here. It has been a problem in the past, and was set up so that things like mu could be passed in directly, but it has caused way more harm than good. I committed a change to yt 3 last night that removed kwargs and replaced with field_parameters, but I think we should consider that in the 2.x branches as well. It's annoying that this is basically a super easy way to shoot yourself in the foot. It's also inconsistent because nearly everywhere else, it *is* data_source, not just source. What does everyone thing of removing kwargs from the data objects and replacing with a field_parameters argument? -Matt On Thu, Aug 9, 2012 at 6:30 PM, Michael Kuhlen wrote:

Hi

I think I've found a bug with serialization and projections with a data_source.

If I do a projection providing a data_source everything is fine:

disk = pf.h.disk((0.5,0.5,0.5), (0,0,1), (10.0,'kpc'), (2.0,'kpc')) pc = PlotCollection(pf) pc.add_projection("NumberDensity","z",weight_field="Density", data_source=disk)

But then, if I do the exact same projection without a data_source, it breaks with an error: 'No field named px'. The full traceback is at http://paste.yt-project.org/show/2637/.

Note that if I first delete the .yt file, then the projection without data_source works just fine.

Mike

-- ********************************************************************* * * * Dr. Michael Kuhlen Theoretical Astrophysics Center * * email: mqk@astro.berkeley.edu UC Berkeley * * cell phone: (831) 588-1468 B-116 Hearst Field Annex # 3411 * * skype username: mikekuhlen Berkeley, CA 94720 * * * ********************************************************************* _______________________________________________ yt-dev mailing list yt-dev@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org