[yt-users] yt-hop: particle IDs question

Stephen Skory stephenskory at yahoo.com
Wed May 13 15:34:43 PDT 2009


Hi Michele,


> I am a new user of yt and I trying to run the yt-hop Halo Finder to build a 
> merger history of halos.

Yes, it is possible.  You need to be running out of trunk.

The first step is to make a copy of 'examples/fastBuildMerge.py' to your favorite location. This is a Python script that builds a Python script that will drive yt. Got it? Good.

In your copy of fastBuildMerge.py, edit the values at the top. It's heavily commented, so I hope you will be able to understand what each does. Reply to the list if you need help understanding them.

You'll want to run HOP on the last (z=0?) timestep by hand to find the halo(es) you wish to track back in time, but it sounds like you've already done that.

Run Python on this script, which outputs the actual script that drives yt. Run the new script and you should get the merger tree.

One final note: as I responded to your email, I noticed I had a typo in the trunk version of fastBuildMerge, which I've updated in r1305, so you should 'svn up' before starting.


Good luck!
 _______________________________________________________
sskory at physics.ucsd.edu           o__  Stephen Skory
http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student
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