[yt-users] Problem using covering_grid as data_source for the photon_simulator

[Markus Haider]

Regarding using ds.ray in the photon simulator: I get the same error as 
I did using the covering grid. However, if I use ds.box it works. Here 
the error I get using ds.ray:

/home/markus/programme/yt-x86_64/src/yt-hg/yt/analysis_modules/photon_simulator/photon_simulator.pyc 
in from_scratch(cls, data_source, redshift, area, exp_time, 
photon_model, parameters, center, dist, cosmology)
     344         width = 0.0
     345         for i, ax in enumerate("xyz"):
--> 346             le, re = data_source.quantities.extrema(ax)
     347             delta_min, delta_max = 
data_source.quantities.extrema("d%s"%ax)
     348             le -= 0.5*delta_max

AttributeError: 'YTRay' object has no attribute 'quantities'

Cheers,
Markus