Hi everyone, I'm trying to make a merger tree on Kraken using parallelHOP and the public yt installation, but am getting this error: Traceback (most recent call last): File "./merger.py", line 9, in <module> MergerTree(files, database='/lustre/scratch/oshea/PopIII_smallbox/halos.db', halo_finder_function=parallelHF) NameError: name 'parallelHF' is not defined All of the requisite Forthon and KD Tree bits seem to be there, and the only thing that I found in the yt install that might be problematic is that I can't access the Forthon directory at /lustre/scratch/proj/yt_common/trunk/src/Forthon-0.8.3/ . I don't know if that could possibly cause problems, but it made me curious. Does anyone have any tips on what's going wrong? Running the exact same script with HaloFinder instead of parallelHF works without problem (just very slowly at lower redshifts). Thanks, Brian