Hi everyone, Thanks for the tips regarding the potential slice on a log-scale; it works great. I've been looking into an alternative way of identifying GMCs in my galaxy disk. Currently, I do this via a density contour, since this roughly equates to how it is done observationally, but I would like to look at gravitationally bound systems as a comparison. The slices I've taken of the potential field suggest many of these will contain several of the clouds I currently define separately. I think the find clumps routine might do what I'd like (which would save me a huge amount of time!) but I am a bit confused as to how to use it. In particular, what is the difference between what the script in the cookbook uses here: http://yt.enzotools.org/doc/cookbook/recipes.html#find-clumps and the derived quantity "_IsBound()"? Does the former use the latter? Is it possible to get a list of cells that comprise each clump such that new properties (mass, angular momentum etc) can be calculated from them? Could someone possible point me to the source code? I couldn't see which routines it was in the yt distribution. Thank you! Elizabeth
Hi, Elizabeth-- The clump handling is done by this routine, for reference: analysis_modules/level_sets/clump_handling.py
and the derived quantity "_IsBound()"? Does the former use the latter? Is it possible to get a list of cells that
The Clump object has an attribute, and the constructor takes and argument, called 'function'. This is a string that is evaluated on each clump before its appended to the hierarchy during find_clumps (which is done in a recursive manner, finding connected sets between two density levels). This defaults to _IsBound.
comprise each clump such that new properties (mass, angular momentum etc) can be calculated from them?
...find_clumps(master_clump,c_min,c_max) appends a hierarchy of children clumps to master_clump. Each clump works like a yt data object, so you can do yt-like things to them, like mass47 = mater_clump.children[0].children[47]['CellMass'].sum() What you typically want are the "finest" clumps, the densest regions that don't have any further substructure. These can be gotten by all_clumps = clump_tools.return_bottom_clumps(master_clump) (check out this http://paste.enzotools.org/show/1678/ for a script on how to plot them) all_clumps is then a flat list that you can work on, which is easier than traversing the hierarchy. (clump_tools has a few other useful tools, as well. One of these days I'll get my butler Alfred to commit the rest of the super awesome clump tools I wrote...) d.
Could someone possible point me to the source code? I couldn't see which routines it was in the yt distribution.
Thank you!
Elizabeth _______________________________________________ yt-users mailing list yt-users@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
-- Sent from my computer.
Hi David and Elizabeth, As a quick note, the underlying level set extraction (topologically connected sets existing inside an AMR3DData object like a sphere or an all_data) can be accessed through the method extract_connected_sets. Clump finding provides quite a lot on top, but the raw connected sets operations can be snagged there. -Matt On Thu, Jun 9, 2011 at 3:37 PM, David Collins <dcollins@physics.ucsd.edu> wrote:
Hi, Elizabeth--
The clump handling is done by this routine, for reference: analysis_modules/level_sets/clump_handling.py
and the derived quantity "_IsBound()"? Does the former use the latter? Is it possible to get a list of cells that
The Clump object has an attribute, and the constructor takes and argument, called 'function'. This is a string that is evaluated on each clump before its appended to the hierarchy during find_clumps (which is done in a recursive manner, finding connected sets between two density levels). This defaults to _IsBound.
comprise each clump such that new properties (mass, angular momentum etc) can be calculated from them?
...find_clumps(master_clump,c_min,c_max)
appends a hierarchy of children clumps to master_clump. Each clump works like a yt data object, so you can do yt-like things to them, like
mass47 = mater_clump.children[0].children[47]['CellMass'].sum()
What you typically want are the "finest" clumps, the densest regions that don't have any further substructure. These can be gotten by
all_clumps = clump_tools.return_bottom_clumps(master_clump) (check out this http://paste.enzotools.org/show/1678/ for a script on how to plot them)
all_clumps is then a flat list that you can work on, which is easier than traversing the hierarchy. (clump_tools has a few other useful tools, as well. One of these days I'll get my butler Alfred to commit the rest of the super awesome clump tools I wrote...)
d.
Could someone possible point me to the source code? I couldn't see which routines it was in the yt distribution.
Thank you!
Elizabeth _______________________________________________ yt-users mailing list yt-users@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
-- Sent from my computer. _______________________________________________ yt-users mailing list yt-users@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
participants (3)
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David Collins -
Elizabeth Tasker -
Matthew Turk