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

[Stephen Skory]

Michele,

> I am not interested in using fastBuildMerge.py, I am only looking for 
> a list of particles IDs associated to each halo. I have my own code to 
> track mergers.

There are several ways to get it.

If you want them from the interactive console, you can do something like this:

> from yt.mods import *
> pf = load('DD0130')
> haloes = HaloFinder(pf)
> particleIDs_biggest_halo = haloes[0]["particle_index"]

If want all the particles saved to disk, once you have the 'haloes' list

> haloes.write_paritcle_lists('parts')

This will write out a hdf5 file with the following information per halo:

login3% h5ls parts.h5/Halo00000060
particle_index           Dataset {171}
particle_position_x      Dataset {171}
particle_position_y      Dataset {171}
particle_position_z      Dataset {171}
particle_velocity_x      Dataset {171}
particle_velocity_y      Dataset {171}
particle_velocity_z      Dataset {171}

The name of the hdf5 group uses the same ID as from the text file from .write_out().

Does that help?

 _______________________________________________________
sskory at physics.ucsd.edu           o__  Stephen Skory
http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student
________________________________(_)_\(_)_______________