[yt-dev] Issue #1261: ProfilePlot should fail more gracefully when used with particle fields (yt_analysis/yt)

[Nathan Goldbaum]

New issue 1261: ProfilePlot should fail more gracefully when used with particle fields
https://bitbucket.org/yt_analysis/yt/issues/1261/profileplot-should-fail-more-gracefully

Nathan Goldbaum:

Right now ParticlePlot will fail when trying to plot particle fields:

```
import yt
ds = yt.load('output_00080/info_00080.txt')
yt.ProfilePlot(ds.all_data(), 'radius', 'particle_mass')
```

This produces a confusing error:

```
IndexError                                Traceback (most recent call last)
/Users/goldbaum/Documents/yt-hg/yt/mods.pyc in <module>()
----> 1 yt.ProfilePlot(ds.all_data(), 'radius', 'particle_mass')

/Users/goldbaum/Documents/yt-hg/yt/visualization/profile_plotter.pyc in __init__(self, data_source, x_field, y_fields, weight_field, n_bins, accumulation, fractional, label, plot_spec, x_log, y_log)
    228                                        accumulation=accumulation,
    229                                        fractional=fractional,
--> 230                                        logs=logs)]
    231
    232         if plot_spec is None:

/Users/goldbaum/Documents/yt-hg/yt/data_objects/profiles.pyc in create_profile(data_source, bin_fields, fields, n_bins, extrema, logs, units, weight_field, accumulation, fractional, deposition)
   1017         setattr(obj, "fractional", fractional)
   1018     if fields is not None:
-> 1019         obj.add_fields([field for field in fields])
   1020     for field in fields:
   1021         if fractional:

/Users/goldbaum/Documents/yt-hg/yt/data_objects/profiles.pyc in add_fields(self, fields)
    111         citer = self.data_source.chunks([], "io")
    112         for chunk in parallel_objects(citer):
--> 113             self._bin_chunk(chunk, fields, temp_storage)
    114         self._finalize_storage(fields, temp_storage)
    115

/Users/goldbaum/Documents/yt-hg/yt/data_objects/profiles.pyc in _bin_chunk(self, chunk, fields, storage)
    427
    428     def _bin_chunk(self, chunk, fields, storage):
--> 429         rv = self._get_data(chunk, fields)
    430         if rv is None: return
    431         fdata, wdata, (bf_x,) = rv

/Users/goldbaum/Documents/yt-hg/yt/data_objects/profiles.pyc in _get_data(self, chunk, fields)
    239         for i, field in enumerate(fields):
    240             units = chunk.ds.field_info[field].units
--> 241             arr[:,i] = chunk[field][filter].in_units(units)
    242         if self.weight_field is not None:
    243             units = chunk.ds.field_info[self.weight_field].units

/Users/goldbaum/Documents/yt-hg/yt/units/yt_array.pyc in __getitem__(self, item)
   1159
   1160     def __getitem__(self, item):
-> 1161         ret = super(YTArray, self).__getitem__(item)
   1162         if ret.shape == ():
   1163             return YTQuantity(ret, self.units, bypass_validation=True)

IndexError: index 94462 is out of bounds for axis 1 with size 94462
```

In addition, even if I use particle fields for the bin and binned fields, I still get a similar error:

```
import yt
ds = yt.load('output_00080/info_00080.txt')
yt.ProfilePlot(ds.all_data(), 'particle_radius', 'particle_mass')
```

```
IndexError                                Traceback (most recent call last)
/Users/goldbaum/Documents/yt-hg/yt/mods.pyc in <module>()
----> 1 yt.ProfilePlot(ds.all_data(), 'particle_radius', 'particle_mass')

/Users/goldbaum/Documents/yt-hg/yt/visualization/profile_plotter.pyc in __init__(self, data_source, x_field, y_fields, weight_field, n_bins, accumulation, fractional, label, plot_spec, x_log, y_log)
    228                                        accumulation=accumulation,
    229                                        fractional=fractional,
--> 230                                        logs=logs)]
    231
    232         if plot_spec is None:

/Users/goldbaum/Documents/yt-hg/yt/data_objects/profiles.pyc in create_profile(data_source, bin_fields, fields, n_bins, extrema, logs, units, weight_field, accumulation, fractional, deposition)
   1017         setattr(obj, "fractional", fractional)
   1018     if fields is not None:
-> 1019         obj.add_fields([field for field in fields])
   1020     for field in fields:
   1021         if fractional:

/Users/goldbaum/Documents/yt-hg/yt/data_objects/profiles.pyc in add_fields(self, fields)
    111         citer = self.data_source.chunks([], "io")
    112         for chunk in parallel_objects(citer):
--> 113             self._bin_chunk(chunk, fields, temp_storage)
    114         self._finalize_storage(fields, temp_storage)
    115

/Users/goldbaum/Documents/yt-hg/yt/data_objects/profiles.pyc in _bin_chunk(self, chunk, fields, storage)
    427
    428     def _bin_chunk(self, chunk, fields, storage):
--> 429         rv = self._get_data(chunk, fields)
    430         if rv is None: return
    431         fdata, wdata, (bf_x,) = rv

/Users/goldbaum/Documents/yt-hg/yt/data_objects/profiles.pyc in _get_data(self, chunk, fields)
    245         else:
    246             weight_data = np.ones(filter.size, dtype="float64")
--> 247         weight_data = weight_data[filter]
    248         # So that we can pass these into
    249         return arr, weight_data, bin_fields

/Users/goldbaum/Documents/yt-hg/yt/units/yt_array.pyc in __getitem__(self, item)
   1159
   1160     def __getitem__(self, item):
-> 1161         ret = super(YTArray, self).__getitem__(item)
   1162         if ret.shape == ():
   1163             return YTQuantity(ret, self.units, bypass_validation=True)

IndexError: index 191131 is out of bounds for axis 1 with size 191131
```

I think the best route here is to fail with a nicer error message, suggesting to use ParticlePlot.