<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi all,<div><br></div><div>sorry, I have a pretty dumb question. </div><div>I have a non-cosmological simulation with only 1 particle. I can get the particle_mass field, but yt throws the following error when I try to grab particle_index:</div><div><br></div><div><i>---------------------------------------------------------------------------------------------------------------------------------</i></div><div><div><i>In [1]: pf = load('CE0001')</i></div><div><i>yt : [INFO ] 2013-04-24 00:32:02,190 Parameters: current_time = 0.00149998503444</i></div><div><i>yt : [INFO ] 2013-04-24 00:32:02,190 Parameters: domain_dimensions = [32 32 32]</i></div><div><i>yt : [INFO ] 2013-04-24 00:32:02,190 Parameters: domain_left_edge = [ 0. 0. 0.]</i></div><div><i>yt : [INFO ] 2013-04-24 00:32:02,190 Parameters: domain_right_edge = [ 1. 1. 1.]</i></div><div><i>yt : [INFO ] 2013-04-24 00:32:02,191 Parameters: cosmological_simulation = 0.0</i></div><div><i><br></i></div><div><i>In [2]: region = pf.h.region([0.5, 0.5, 0.5], [0.0, 0.0, 0.0], [1.0, 1.0, 1.0])</i></div><div><i>yt : [INFO ] 2013-04-24 00:32:05,802 Getting the binary hierarchy</i></div><div><i>yt : [INFO ] 2013-04-24 00:32:05,805 Finished with binary hierarchy reading</i></div><div><i><br></i></div><div><i>In [3]: region['particle_mass']</i></div><div><i>yt : [INFO ] 2013-04-24 00:32:12,685 Getting particle_mass using ParticleIO</i></div><div><i>Out[3]: array([ 6585896.1408])</i></div><div><i><br></i></div><div><i>In [4]: region['particle_index']</i></div><div><i>---------------------------------------------------------------------------</i></div><div><i>KeyError Traceback (most recent call last)</i></div><div><i>/Users/jcpassy/Work/yt-x86_64/src/yt-hg/scripts/iyt in <module>()</i></div><div><i>----> 1 region['particle_index']</i></div><div><i><br></i></div><div><i>/Users/jcpassy/Work/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in __getitem__(self, key)</i></div><div><i> 328 if key not in self.fields:</i></div><div><i> 329 self.fields.append(key)</i></div><div><i>--> 330 self.get_data(key)</i></div><div><i> 331 return self.field_data[key]</i></div><div><i> 332 </i></div><div><i><br></i></div><div><i>/Users/jcpassy/Work/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in get_data(self, fields, in_grids, force_particle_read)</i></div><div><i> 2614 pass</i></div><div><i> 2615 if field not in self.hierarchy.field_list and not in_grids:</i></div><div><i>-> 2616 if self._generate_field(field):</i></div><div><i> 2617 continue # True means we already assigned it</i></div><div><i> 2618 mylog.info("Getting field %s from %s", field, len(self._grids))</i></div><div><i><br></i></div><div><i>/Users/jcpassy/Work/yt-x86_64/src/yt-hg/yt/data_objects/data_containers.pyc in _generate_field(self, field)</i></div><div><i> 361 return True</i></div><div><i> 362 else: # Can't find the field, try as it might</i></div><div><i>--> 363 raise KeyError(field)</i></div><div><i> 364 </i></div><div><i> 365 def _generate_field_in_grids(self, field, num_ghost_zones=0):</i></div><div><i><br></i></div><div><i>KeyError: 'particle_index'</i></div></div><div><div><i>---------------------------------------------------------------------------------------------------------------------------------</i></div><div><br></div><div>However, the field is there:</div><div><br></div><div><i>---------------------------------------------------------------------------------------------------------------------------------</i></div><div><i>[ 0:30:13] Obiwan:$ h5ls CE0001.cpu0000/Grid00000004</i></div><div><div><i>Dark_Matter_Density Dataset {52, 52, 52}</i></div><div><i>Density Dataset {52, 52, 52}</i></div><div><i>TotalEnergy Dataset {52, 52, 52}</i></div><div><i>particle_index Dataset {1}</i></div><div><i>particle_mass Dataset {1}</i></div><div><i>particle_position_x Dataset {1}</i></div><div><i>particle_position_y Dataset {1}</i></div><div><i>particle_position_z Dataset {1}</i></div><div><i>particle_type Dataset {1}</i></div><div><i>particle_velocity_x Dataset {1}</i></div><div><i>particle_velocity_y Dataset {1}</i></div><div><i>particle_velocity_z Dataset {1}</i></div><div><i>x-velocity Dataset {52, 52, 52}</i></div><div><i>y-velocity Dataset {52, 52, 52}</i></div><div><i>z-velocity Dataset {52, 52, 52}</i></div><div><i>[ 0:30:13] Obiwan:$ h5ls -d CE0001.cpu0000/Grid00000004/particle_index</i></div><div><i>particle_index Dataset {1}</i></div><div><i> Data:</i></div><div><i> (0) 0</i></div></div><div><div><i>---------------------------------------------------------------------------------------------------------------------------------</i></div></div><div><br></div><div>Am I missing something obvious?</div><div><br></div><div>Thanks a lot for you help,</div><div><br></div><div>JC</div><div></div></div></body></html>