[yt-users] hierarchy file for light cone simulation

Matthew Turk matthewturk at gmail.com
Tue Mar 15 12:49:21 PDT 2011


Hi Britton,

On Tue, Mar 15, 2011 at 12:35 PM, Britton Smith <brittonsmith at gmail.com> wrote:
> Hi everyone,
>
> I'm trying to make some projections of the data from the Santa Fe Light Cone
> simulation, but it's getting hung trying to parse the hierarchy file.  After
> looking around, I noticed that the one dataset that I had success with has a
> different format for the hierarchy file than the ones that aren't working.
> The ones that are working have hierarchy files that look like this:
>
> Grid = 1
> GridRank          = 3
> GridDimension     = 134 70 70
> GridStartIndex    = 3 3 3
> GridEndIndex      = 130 66 66
> GridLeftEdge      = 0 0 0
> GridRightEdge     = 0.25 0.125 0.125
> Time              = 101.45398694554
> SubgridsAreStatic = 0
> NumberOfBaryonFields = 7
> FieldType = 0 1 2 4 5 6 22
> BaryonFileName =
> /dsgpfs/projects/enzo/ux453739/GC512_L7_New/RD0009/RD0009.cpu0000
> CourantSafetyNumber    = 0.400000
> PPMFlatteningParameter = 0
> PPMDiffusionParameter  = 0
> PPMSteepeningParameter = 0
> NumberOfParticles   = 445435
> ParticleFileName =
> /dsgpfs/projects/enzo/ux453739/GC512_L7_New/RD0009/RD0009.cpu0000
> GravityBoundaryType = 0
> Pointer: Grid[1]->NextGridThisLevel = 2
>
> The ones that aren't working have formats like this:
>
> Grid = 1
> GridRank          = 3
> GridDimension     = 134 70 70
> GridStartIndex    = 3 3 3
> GridEndIndex      = 130 66 66
> GridLeftEdge      = 0 0 0
> GridRightEdge     = 0.25 0.125 0.125
> Time              = 128.98486432526
> SubgridsAreStatic = 0
> FileName       = RD0012.cpu0000
> GroupName      = /Grid00000001
> NumberOfBaryonFields = 7
> FieldType = 0 1 2 4 5 6 22
> CourantSafetyNumber    = 0.400000
> PPMFlatteningParameter = 0
> PPMDiffusionParameter  = 0
> PPMSteepeningParameter = 0
> NumberOfParticles   = 408561
> GravityBoundaryType = 0
> Pointer: Grid[1]->NextGridThisLevel = 2
>
> The first type seems to be the standard.  Is there anything I can do to make
> this nonstandard hierarchy format work with YT?
>

Okay, I have seen some of this before.  My understanding is that this
hierarchy format is basically broken.  It worked with one version of
Enzo, but will not restart (cleanly) with any current version of Enzo
-- in particular, the problem seems to be not just in the ordering of
the lines in each grid entry, but in the actual content of the lines
themselves.

Additionally, not only is it broken for all current and most past
versions of Enzo, but it doesn't also doesn't have its own
VersionNumber value in the parameter file, so there's no easy way to
switch between mechanisms for parsing the hierarchy without actually
parsing the hierarchy.

One could theoretically write a whole bunch of conditionals that
switch between methods, but I believe supporting this hierarchy format
would add substantial performance hits to the hierarchy parser, which
as of right now actually takes up a substantial amount of time anyway
in the instantiation of light cone-size datasets.  Because it's a
broken hierarchy format, it's not supported anymore by any Enzo
versions and supporting it would incur either a substantial
performance hit or some additional largely-unused code to be included
as an alternate, I'm not sure I can really justify supporting it as an
additional mechanism.

Maybe try pre-processing it to make it look like a standard hierachy?

-Matt

> Thanks,
> Britton
>
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