Hi all,

I'm trying to create two derived fields (one for stellar density, and one for dark matter density) based on these from yt2. I'm running yt 3.2.3, and the star_density and dm_density fields seem to have been removed. So far, the yt2 code has transferred fine, with minimal changes:
Besides those two quirks, the code runs (I'm able to add a field using ds.add_field), but I get an error when I try to access the data using ds.all_data()['star_density'] (it seems now is when the field is actually computed).

I get the following error:
<ipython-input-5-1af8fbcb718a> in _spdensity(field, data)
      1 def _spdensity(field, data):
----> 2     blank = np.zeros(data.ActiveDimensions, dtype='float64')
      3     if data['particle_position_x'].size == 0: return blank
      4     filter = data['creation_time'] > 0.0
      5     if not filter.any(): return blank
AttributeError: 'YTRegion' object has no attribute 'ActiveDimensions'

All the examples of ActiveDimensions that I saw in the docs and source accessed ActiveDimensions as a property of some grid (i.e. g.ActiveDimensions). Is there a simple way to access that from the data/YTRegion object that I'm missing? I can access ds.index.grids and take the first grid there, but ActiveDimensions differs across the grids (And when I try to do this from within _spdensity, data doesn't have an index.grids object, just fake_index (which can't access the grids)). Is there something I'm missing?