Okay, I have pulled up some source code and the RD0035 dataset and looked at this. Here's what's going on.
The sphere object gets all candidate grids, from a first pass:
http://yt.enzotools.org/browser/trunk/yt/lagos/HierarchyType.py#L418
This is the first pass estimate at which grids could be members, which then gets cut down in the actual sphere object; these two grids are red herrings. Note that this checks the grid dx < radius, as this is important in a moment. There are 36 particles within this region, which I was able to find by turning off the criteria that grids have dx > radius of the sphere. The ids of the grids in which these particles live are:
array([ 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162648., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757., 162757.])
and the dx's are:
array([ 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656, 0.00097656])
I'm torn about this issue. On the one hand, I kind of don't like the idea of giving back data from grids with dx > radius; this doesn't sit well with me. On the other, particles are not necessarily supposed to behave the same way, so perhaps in this case it would be appropriate. Changing the requirement from
gridI = na.where(na.logical_and((self.gridDxs<=radius)[:,0],(dist < (radius + long_axis))) == 1)
to
gridI = na.where(na.logical_and((self.gridDxs<=2.0*radius)[:,0],(dist < (radius + long_axis))) == 1)
would satisfy me, and would work with this particular use case. What do you think?
I guess a secondary question would be about the meaning of this halo; it's 36 particles, but they're all within a radius of less than the dx of their host grid. Once I've changed the requirement for getting grids to be 2*radius, we end up with three cells included. This profile would be uninformative.
-Matt
On Tue, Mar 24, 2009 at 11:03 AM, Stephen Skory stephenskory@yahoo.com wrote:
Hi guys,
Maybe you could try increasing the value of PROFILE_RADIUS_THRESHOLD in HaloProfiler.py. Right now, it's set to 2, meaning that it will allow profiles for halos whose outer radii are only 2 times the inner radii. That's probably too generous. Even halos of that size should probably be ignored.
The radius of this problem halo/pf.h.get_smallest_dx() = 26, so I don't think that's the issue.
Looking at the hierarchy, below are the two grids listed in sphere._grids. The sphere being cut is
sp = pf.h.sphere([6.983622952e-01, 3.006639125e-01, 4.988738710e-01],8.156776433e-04)
I notice that the center of the halo isn't in these grids. Could that be the problem?
Grid = 163293 GridRank = 3 GridDimension = 14 22 20 GridStartIndex = 3 3 3 GridEndIndex = 10 18 16 GridLeftEdge = 0.693359375 0.296875 0.4921875 GridRightEdge = 0.697265625 0.3046875 0.4990234375 Time = 584.25598986586 SubgridsAreStatic = 0 FileName = RD0035.cpu0150 GroupName = /Grid00163293 NumberOfBaryonFields = 7 FieldType = 0 1 2 4 5 6 22 CourantSafetyNumber = 0.100000 PPMFlatteningParameter = 0 PPMDiffusionParameter = 0 PPMSteepeningParameter = 0 NumberOfParticles = 273 GravityBoundaryType = 2 Pointer: Grid[163293]->NextGridThisLevel = 0 Pointer: Grid[163293]->NextGridNextLevel = 163294
Grid = 163917 GridRank = 3 GridDimension = 16 14 10 GridStartIndex = 3 3 3 GridEndIndex = 12 10 6 GridLeftEdge = 0.701171875 0.296875 0.498046875 GridRightEdge = 0.7060546875 0.30078125 0.5 Time = 584.25598986586 SubgridsAreStatic = 0 FileName = RD0035.cpu0150 GroupName = /Grid00163917 NumberOfBaryonFields = 7 FieldType = 0 1 2 4 5 6 22 CourantSafetyNumber = 0.100000 PPMFlatteningParameter = 0 PPMDiffusionParameter = 0 PPMSteepeningParameter = 0 NumberOfParticles = 84 GravityBoundaryType = 2 Pointer: Grid[163917]->NextGridThisLevel = 0 Pointer: Grid[163917]->NextGridNextLevel = 163918
_______________________________________________________ sskory@physics.ucsd.edu o__ Stephen Skory 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