more non-unique particles in enzo and how to deal with them
Hi everyone, Stephen's latest update of his new parallel hop to check for unique-ness of particle indices has shed light on another problem. In a recent simulation run with the devel/trunk version of enzo, I have found the particle numbers are no longer unique when star particles are generated. Originally, the star particle indices by adding to the number of dark matter particles, such that if you had N dm particles and M star particles, the dm particle indices when from 0 to N-1 and the star particle indices went from N to N+M-1. However, now it seems that the star particles simply go from 0 to M. Before I go any further, I will mention that the star particles can be differentiated from the dark matter particles by the particle_type data, so we're not totally screwed. The point is that for the time being, hop no longer works. The question is this: what is the best solution for dealing with this? I am more than willing to write something to remap the particle indices, but that doesn't fix the underlying problem. I have already done something similar to this for a different application, so I can do it quickly. OR, something can be done to hop to read in particle type. Clearly, this question is mainly for Stephen, but anyone should feel free to weigh in. What is the best solution? Britton
Britton,
Stephen's latest update of his new parallel hop to check for unique-ness of particle indices has shed light on another problem. In a recent simulation run with the devel/trunk version of enzo, I have found the particle numbers are no longer unique when star particles are generated. Originally, the star particle indices by adding to the number of dark matter particles, such that if you had N dm particles and M star particles, the dm particle indices when from 0 to N-1 and the star particle indices went from N to N+M-1.
Unfortunately, Ji-hoon Kim addressed this issue last month <http://hg.spacepope.org/week-of-code/rev/bc61ccd0f247>, which you may not be aware of. Obviously it's too late for this dataset!
However, now it seems that the star particles simply go from 0 to M. Before I go any further, I will mention that the star particles can be differentiated from the dark matter particles by the particle_type data, so we're not totally screwed. The point is that for the time being, hop no longer works. The question is this: what is the best solution for dealing with this? I am more than willing to write something to remap the particle indices, but that doesn't fix the underlying problem. I have already done something similar to this for a different application, so I can do it quickly. OR, something can be done to hop to read in particle type. Clearly, this question is mainly for Stephen, but anyone should feel free to weigh in. What is the best solution?
I see several options. You could filter out all the stars like this: notstars = (self._data_source["particle_type"] != star) and then in HaloFinding.py add a '[notstars]' to all the arrays where the particle data is handled and handed off to Parallel HOP. If you have 'creation_time' you could just try setting 'dm_only=True' in the HaloFinder call. I think you could easily write a script to fix the dataset itself (on a copy, not the original, of course). Use h5py to open the files, and read in the particle_index and particle_type fields. SO something like this: pi = file["Grid00000234"]["particle_index"] ct = file["Grid00000234"]["particle_type"] tochange = (ct == star) tochange *= (number of dark matter particles) pi += tochange and then delete the old particle_index field from the file, and replace it with this new pi array. I'll let you know what else I come up with. Good luck! _______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student ________________________________(_)_\(_)_______________
Stephen, so is this fix (to enzo) only in WOC and not in the dev trunk? On Dec 4, 2009, at 4:37 PM, Stephen Skory wrote:
Britton,
Stephen's latest update of his new parallel hop to check for unique- ness of particle indices has shed light on another problem. In a recent simulation run with the devel/trunk version of enzo, I have found the particle numbers are no longer unique when star particles are generated. Originally, the star particle indices by adding to the number of dark matter particles, such that if you had N dm particles and M star particles, the dm particle indices when from 0 to N-1 and the star particle indices went from N to N+M-1.
Unfortunately, Ji-hoon Kim addressed this issue last month <http://hg.spacepope.org/week-of-code/rev/bc61ccd0f247
, which you may not be aware of. Obviously it's too late for this dataset!
However, now it seems that the star particles simply go from 0 to M. Before I go any further, I will mention that the star particles can be differentiated from the dark matter particles by the particle_type data, so we're not totally screwed. The point is that for the time being, hop no longer works. The question is this: what is the best solution for dealing with this? I am more than willing to write something to remap the particle indices, but that doesn't fix the underlying problem. I have already done something similar to this for a different application, so I can do it quickly. OR, something can be done to hop to read in particle type. Clearly, this question is mainly for Stephen, but anyone should feel free to weigh in. What is the best solution?
I see several options. You could filter out all the stars like this:
notstars = (self._data_source["particle_type"] != star)
and then in HaloFinding.py add a '[notstars]' to all the arrays where the particle data is handled and handed off to Parallel HOP. If you have 'creation_time' you could just try setting 'dm_only=True' in the HaloFinder call.
I think you could easily write a script to fix the dataset itself (on a copy, not the original, of course). Use h5py to open the files, and read in the particle_index and particle_type fields. SO something like this:
pi = file["Grid00000234"]["particle_index"] ct = file["Grid00000234"]["particle_type"] tochange = (ct == star) tochange *= (number of dark matter particles) pi += tochange
and then delete the old particle_index field from the file, and replace it with this new pi array.
I'll let you know what else I come up with.
Good luck!
_______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student ________________________________(_)_\(_)_______________
_______________________________________________ Yt-dev mailing list Yt-dev@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
Eric Hallman Google Voice: (312) 725-HMAN hallman13@gmail.com
Hi Eric,
Stephen, so is this fix (to enzo) only in WOC and not in the dev trunk?
Yes. My understanding is that there are no (current) plans to backport it, or many of the other star maker changes. -Matt
Eric,
so is this fix (to enzo) only in WOC and not in the dev trunk?
I don't know if it's broken in dev trunk. Making particle indexes globally unique (or fixing it, I'm not sure it ever worked before I looked at it) was one of the first things I did to Enzo years ago. I don't know when it broke after that, if it was before or after WoC got split. Many people don't care about it, so they don't look for it when they make changes. But now that this new halo finder requires it, hopefully it won't be ignored again! _______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student ________________________________(_)_\(_)_______________
It is broken in dev trunk, since the run britton is talking about was done with dev trunk. So the particle number issue is still there, at least as relates to yt parallel hop. On Dec 4, 2009, at 4:56 PM, Stephen Skory wrote:
Eric,
so is this fix (to enzo) only in WOC and not in the dev trunk?
I don't know if it's broken in dev trunk. Making particle indexes globally unique (or fixing it, I'm not sure it ever worked before I looked at it) was one of the first things I did to Enzo years ago. I don't know when it broke after that, if it was before or after WoC got split. Many people don't care about it, so they don't look for it when they make changes. But now that this new halo finder requires it, hopefully it won't be ignored again!
_______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student ________________________________(_)_\(_)_______________ _______________________________________________ Yt-dev mailing list Yt-dev@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
Eric Hallman Google Voice: (312) 725-HMAN hallman13@gmail.com
It is definitely broken in devel trunk, but I don't know for how long. What has been established, both within and outside of this conversation, is that this is an enzo bug and not something someone intended. Thus, nothing should be done to existing tools to account for this. I will write something to fix our data and for anyone else who might have this problem. I will look into fixing this in the devel/trunk as well. The bigger issue is that devel/trunk is on its way out as far as getting its bugs fixed and it's probably time for the rest of us to move to the week of code branch for doing science. That is a whole other conversation. On Fri, Dec 4, 2009 at 4:59 PM, Eric Hallman <hallman13@gmail.com> wrote:
It is broken in dev trunk, since the run britton is talking about was done with dev trunk. So the particle number issue is still there, at least as relates to yt parallel hop.
On Dec 4, 2009, at 4:56 PM, Stephen Skory wrote:
Eric,
so is this fix (to enzo) only in WOC and not in the dev trunk?
I don't know if it's broken in dev trunk. Making particle indexes globally unique (or fixing it, I'm not sure it ever worked before I looked at it) was one of the first things I did to Enzo years ago. I don't know when it broke after that, if it was before or after WoC got split. Many people don't care about it, so they don't look for it when they make changes. But now that this new halo finder requires it, hopefully it won't be ignored again!
_______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory http://physics.ucsd.edu/~sskory/ <http://physics.ucsd.edu/%7Esskory/>_.>/ _Graduate Student ________________________________(_)_\(_)_______________
_______________________________________________ Yt-dev mailing list Yt-dev@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
Eric Hallman Google Voice: (312) 725-HMAN hallman13@gmail.com
_______________________________________________ Yt-dev mailing list Yt-dev@lists.spacepope.org http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
The bigger issue is that devel/trunk is on its way out as far as getting its bugs fixed and it's probably time for the rest of us to move to the week of code branch for doing science. That is a whole other conversation.
I know this isn't really the appropriate venue for a discussion of enzo issues, but I would like to mention that I'm heading to UCSD momentarily for a couple of days of conversations with Mike and the UCSD Enzo folks regarding the Enzo petascale project (more specifically, the Blue Waters PRAC project). One of the points of discussion is going to be the next public release of Enzo. In our conversation yesterday, Mike and I specifically talked about the code fractionation and what to do about it, though we didn't reach any conclusions. If anybody has any thoughts about this, I encourage you to email me directly before Monday. Thanks! Brian
participants (5)
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Brian O'Shea -
Britton Smith -
Eric Hallman -
Matthew Turk -
Stephen Skory