Hi folks, I just tried to do some halo-finding with yt-3 using Hop (the current tip; rev 3cfb38afe34d), and it died somewhere after calling 'regroup' with this error: Traceback (most recent call last): File "hop.py", line 11, in <module> halo_list = HaloFinder(pf, subvolume=my_subregion) File "/mnt/a/u/sciteam/bwoshea/yt-3.0/src/yt-hg/yt/analysis_modules/halo_finding/halo_objects.py", line 2440, in __init__ self._join_halolists() File "/mnt/a/u/sciteam/bwoshea/yt-3.0/src/yt-hg/yt/analysis_modules/halo_finding/halo_objects.py", line 1889, in _join_halolists self._groups.sort(haloCmp) File "/mnt/a/u/sciteam/bwoshea/yt-3.0/src/yt-hg/yt/analysis_modules/halo_finding/halo_objects.py", line 1888, in haloCmp return cmp(h1.center_of_mass()[0], h2.center_of_mass()[0]) File "/mnt/a/u/sciteam/bwoshea/yt-3.0/src/yt-hg/yt/utilities/parallel_tools/parallel_analysis_interface.py", line 191, in single_proc_results retval = func(self, *args, **kwargs) File "/mnt/a/u/sciteam/bwoshea/yt-3.0/src/yt-hg/yt/analysis_modules/halo_finding/halo_objects.py", line 158, in center_of_mass c = (com * pm).sum(axis=1) / pm.sum() File "/mnt/a/u/sciteam/bwoshea/yt-3.0/src/yt-hg/yt/units/yt_array.py", line 648, in __rmul__ return YTArray(super(YTArray, self).__rmul__(lo)) File "/mnt/a/u/sciteam/bwoshea/yt-3.0/src/yt-hg/yt/units/yt_array.py", line 910, in __array_wrap__ ret_class = get_binary_op_return_class(cls1, cls2) File "/mnt/a/u/sciteam/bwoshea/yt-3.0/src/yt-hg/yt/units/yt_array.py", line 1045, in get_binary_op_return_class raise RuntimeError("Operations are only defined on pairs of objects" RuntimeError: Operations are only defined on pairs of objectsin which one is a subclass of the other It was functional roughly two weeks ago (on May 10), when I successfully did halo-finding on the same machine with yt-3. Looking at the errors, it seems to be something more general than Hop functionality, but I'm not entirely sure. Does anybody have any thoughts on this? Also, for the sake of completeness, you can see my batch and python scripts: http://paste.yt-project.org/show/4681/ http://paste.yt-project.org/show/4682/ And the full output log from the run: http://paste.yt-project.org/show/4683/ And, again, this is using the current tip of yt-3. Thanks! --Brian