[Yt-dev] EnzoFOF merger tree

[Matthew Turk]

Hi John,

This is pretty cool!  Thanks for sharing this.

What I think would very cool is if we could apply this particular type
of graphviz output (and I know Stephen has also done a lot with
graphviz, so maybe he has something to suggest) to the creation of
level set (i.e., clump) diagrams.

In particular, the Vascucci and Cole-McLoughlin algorithm for level
set identification, which I may finally be able to implement after two
years of dancing around it, would provide us with grid cell dendograms
based on arbitrary quantities.  It would be great if there was a
hierarchical graphviz output for that (or for our current Clump
system.)  One idea might be to yank the hierarchical dotfile writer
for graphviz into something abstract, where you would call a function
with a list of root nodes, and supply to it the name of a method that
provides supplemental information as well as the name of the list of
child nodes.  What do you think?  Then we could have a single graphviz
output method that works with clumps and both merger tree
implementations?

-Matt

On Fri, Jan 14, 2011 at 1:02 AM, John Wise <jwise at astro.princeton.edu> wrote:
> Hi all,
>
> I just extended Matt's merger tree that works on enzo's inline FOF halo finder to work on multiple outputs, and build a complete merger tree.  It produces DOT (Graphviz) files.  I tried to make it simple to use and put in the necessary docstrings.  Here's an example to make a merger tree from z = 15->7 only including halos with >500 particles.
>
> """
> from yt.mods import *
> import yt.analysis_modules.halo_merger_tree.api as hm
>
> tree = hm.EnzoFOFMergerTree((7.0,15.0), load_saved=True)
> #tree.build_tree(0, max_children=4)
> tree.build_tree(0, min_particles=500)
> tree.write_dot()
> """
>
> The load_saved argument will load the pickled results from previous calculations.  It will save it by default if it's false.
>
> Here's the result from the most massive halo in a 256^3 sim.  Careful, it's large!  1.9MB, 4325x7461 pix
> http://www.astro.princeton.edu/~jwise/pics/merger-tree.png
>
> If you try it out, please let me know of any problems!
>
> Cheers,
> John
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