Hi all,
With the new setup, I'm getting negative values for the center_of_mass() for some of the haloes in L7 running parallel HOP. It's a small fraction of the total. I am not getting this effect on smaller datasets for this reason.
Because L7 takes a while to run through HOP, I haven't been able to do much testing yet. I've only run this on Ranger. I'm going to try on Kraken soon, but I suspect I'll get the same thing. I also suspect I'd get the same problem with parallel FOF. I haven't tested this on a serial run on L7, because it takes a long time. I'd guess that it would work OK. I'll see if I can get that going, too.
Matt, can you think of anything you changed when you did the HaloFinding switchover that would affect this?
I'll see what I can figure out, but I just wanted to see if anyone (Matt in particular) had some ideas of where this is coming from before I jump headlong into this.
Thanks!
_______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student ________________________________(_)_\(_)_______________
Hi Stephen,
With the new setup, I'm getting negative values for the center_of_mass() for some of the haloes in L7 running parallel HOP. It's a small fraction of the total. I am not getting this effect on smaller datasets for this reason.
Which new setup? With the patch including hop_numpy.h applied? And, can you tell us what these negative values look like?
Matt, can you think of anything you changed when you did the HaloFinding switchover that would affect this?
Not that I can think of. I got the same results on the small datasets; hop should be called in the same way. Can you show us one or two of the lines where you get the negative values?
-Matt
Are these negative numbers for halos that are sitting on domain boundaries or are they completely nonsensical? If it's the former, then maybe something subtle has changed with how the code deals with periodic boundaries. Just a thought.
Britton
On Mon, Apr 27, 2009 at 10:57 AM, Matthew Turk matthewturk@gmail.comwrote:
Hi Stephen,
With the new setup, I'm getting negative values for the center_of_mass()
for some of the haloes in L7 running parallel HOP. It's a small fraction of the total. I am not getting this effect on smaller datasets for this reason.
Which new setup? With the patch including hop_numpy.h applied? And, can you tell us what these negative values look like?
Matt, can you think of anything you changed when you did the HaloFinding
switchover that would affect this?
Not that I can think of. I got the same results on the small datasets; hop should be called in the same way. Can you show us one or two of the lines where you get the negative values?
-Matt _______________________________________________ Yt-dev mailing list Yt-dev@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
Guys,
the problem was with my threshold_adjustment parameter. It was being applied to the coordinates for the maximum density particle as well as the value of the density. So the effect was strongest when I was using 64 threads, and it was severely messing with the center_of_mass which uses the maximum density point. I committed a fix it r1284.
Sorry about the unnecessary list chatter.
_______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student ________________________________(_)_\(_)_______________
participants (3)
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Britton Smith -
Matthew Turk -
Stephen Skory