Jean-Claude,
sphere = pf.h.sphere([0.5 0.5 0.5],1.0) hop_results = lagos.hop.HopList(sphere, 80.000000)
which I copied from the merger code, so the thresholds were the same, unfortunately.
Darn it. Another simple question is (and I'm guessing 'no' is the answer), are there stars in your simulation? If yes, did you do all the runs of HOP with them considered (or excluded)? Are you comparing the same columns of the output of HOP? Are you sure you're not comparing the most-dense particle position to the calculated center of mass? In the text file output of HOP, the first columns of positions are the most-dense particle, while the merger tree should be using the center of mass (unless I've done something wrong!). I'm thinking of what else could be going on... _______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student ________________________________(_)_\(_)_______________