[yt-users] ZeroDivisionError accessing field from ray in spherical 1D FLASH data

[Matthew Turk]

Hi Luke,

You didn't do anything wrong.  :)  yt should be able to accept rays
through "ray" that are orthogonal to the axes, but it can't because of
some sloppiness.  You have two options -- either use "ortho_ray"
instead of "ray", which will make it orthogonal (and probably be a bit
faster) or add jitter to the tune of 1e-12 to your 0.0 entries.

-Matt

On Mon, Jun 23, 2014 at 11:44 AM, Luke Zoltan Kelley
<lkelley at cfa.harvard.edu> wrote:
> Hello yt-users,
>
> Just starting using YT, please forgive simple problems.
>
> I have 1D spherical FLASH data which I'm trying to plot.  I thought I should use a 'ray', so I created one as such and try to access the data but I'm getting a ZeroDivision Error:
>
> from yt.mods import *
> pf = load('starwind_hdf5_plt_cnt_0000')
> In [141]: ray = pf.h.ray([0.0,0.0,0.0],[1.0e11,0.0,0.0], fields=["Density"])
> In [142]: ray['Density']
>
> yt : [INFO     ] 2014-06-23 12:40:51,841 Getting field t from 138
> ERROR: ZeroDivisionError: float division [IPython.core.interactiveshell]
> astropy: [ERROR    ] 2014-06-23 12:40:51,846 ZeroDivisionError: float division
> ---------------------------------------------------------------------------
> ZeroDivisionError                         Traceback (most recent call last)
> <ipython-input-142-c8a80a171d35> in <module>()
> ----> 1 ray['Density']
>
> /Users/lzkelley/Applications/yt/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in __getitem__(self, key)
>     316             if key not in self.fields:
>     317                 self.fields.append(key)
> --> 318             self.get_data(key)
>     319         return self.field_data[key]
>     320
>
> /Users/lzkelley/Applications/yt/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in get_data(self, fields, in_grids)
>     523             self[field] = np.concatenate(
>     524                 [self._get_data_from_grid(grid, field)
> --> 525                  for grid in self._grids])
>     526             if not self.field_data.has_key(field):
>     527                 continue
>
> /Users/lzkelley/Applications/yt/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in save_state(self, grid, field, *args, **kwargs)
>      79         old_keys = grid.field_data.keys()
>      80         grid.field_parameters = self.field_parameters
> ---> 81         tr = func(self, grid, field, *args, **kwargs)
>      82         grid.field_parameters = old_params
>      83         grid.field_data = YTFieldData( [(k, grid.field_data[k]) for k in old_keys] )
>
> /Users/lzkelley/Applications/yt/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in _get_data_from_grid(self, grid, field)
>     689     @restore_grid_state
>     690     def _get_data_from_grid(self, grid, field):
> --> 691         mask = np.logical_and(self._get_cut_mask(grid),
>     692                               grid.child_mask)
>     693         if field == 'dts': return self._dts[grid.id][mask]
>
> /Users/lzkelley/Applications/yt/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in check_cache(self, grid)
>     109         elif grid.id not in self._cut_masks or \
>     110                 hasattr(self, "_boolean_touched"):
> --> 111             cm = func(self, grid)
>     112             self._cut_masks[grid.id] = cm
>     113         return self._cut_masks[grid.id]
>
> /Users/lzkelley/Applications/yt/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in _get_cut_mask(self, grid)
>     704         ts = np.zeros(grid.ActiveDimensions, dtype='float64')
>     705         VoxelTraversal(mask, ts, dts, grid.LeftEdge, grid.RightEdge,
> --> 706                        grid.dds, self.center, self.vec)
>     707         self._dts[grid.id] = np.abs(dts)
>     708         self._ts[grid.id] = np.abs(ts)
>
> /Users/lzkelley/Applications/yt/yt-x86_64/src/yt-hg/yt/utilities/lib/RayIntegrators.so in yt.utilities.lib.RayIntegrators.VoxelTraversal (yt/utilities/lib/RayIntegrators.c:3408)()
>
> ZeroDivisionError: float division
>
>
> yt instinfo
> Version = 2.6.1
> Changeset = c7bae05dd4ef
>
>
> Any ideas what I'm doing wrong?
> Thanks!
> Luke
>
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