Hi Matt,
>My guess is actually the width argument -- you're setting it to 1.0,
> After using the debugger as you suggested and looking more closely it seems
> that LE is still an empty list because self.bricks = None even after a call
> to self.partition_grids(). The latter is not working properly because
> self._brick_collection.source._grids is an empty ndarray. For example, I
> get the following DEBUG message before the fatal error:
>
> yt DEBUG 2010-12-30 16:40:49,932 Preloading ['Density'] from 0
> grids
>
> I now need to track down why _grids is not being filled appropriately; all
> the other grid-type-lists I have found are properly filled.
and the center to 0.5, 0.5, 0.5. Can you try with:
W = pf['unitary']
c = 0.5*(pf.domain_right_edge + pf.domain_left_edge)
which should grab all the bricks?