Hi Joseph, On Tue, May 28, 2013 at 11:07 PM, Joseph Smidt wrote:

Nathan,

Thanks for your response. I believe I have the lastest version of yt. I get this if I do an hg tip:

[jsmidt@mu-fe1 yt]$ hg tip changeset: 8217:fb6cce6a2936 branch: yt tag: tip user: Nathan Goldbaum date: Mon May 27 09:24:17 2013 -0700 files: yt/config.py description: Bumping the gold standard revision to gold0008.

Now the checkpoint output is slightly different than a normal data dump. for instance, the DD0047/output_0047 file has this comment at the top which cannot be read into yt without being removed:

# WARNING! This is a checkpoint dump! Lots of data! InitialCycleNumber = 228 InitialTime = 20.046508365013 InitialCPUTime = 0

And there are additional fields like Acceleration fields with these checkpoint dumps. So I was wondering if this other error when finding the max values of fields is also checkpoint dump specific as the structure seems slightly different compared to normal data dumps. Thanks again.

I wrote the checkpoint dump mechanism in Enzo, and it wasn't meant to be used for analysis. It stores the fluxes (where they exist), the acceleration, ghost zones, "old" baryon fields, and probably some other things I've forgotten now. The idea was to dump all of the internal data structures that accumulate over the course of a timestep, and then load them in at a later time, hopefully preserving the exact state. (For what it's worth, it never was as successful as reproducing the exact state of the computation as I had hoped it would be.) So my guess is that you're seeing issues with the ghost zones changing the dimensions of the grids in funny ways. In many ways, the checkpoint dumps are more similar to the analysis conducted inline in Enzo than they are to analysis conducted of standard Enzo data dumps -- the ghost zones will need to be sliced off and the old/new fields will need to be interpolated to the centered time. So to make a long story short, when I use checkpoint dumps in Enzo to restart the computation, I don't use them for analysis -- I also have Enzo output standard data dumps and use those. If we were to try to make this work, it would need a new IO handler similar to the Inline IO handler which interpolates between times and slices off ghost zones. -Matt

On Tue, May 28, 2013 at 7:45 PM, Joseph Smidt wrote:

...

Hey everyone,

My Enzo simulation has refined to enough levels that I need to make checkpoint dumps mid-timestep and do YT analysis from there. I can read in the checkpoint dump but when I go to find the max density I get this error: http://pastebin.com/2mNVxNyW

Anybody have any idea what is going on and how to fix this? Also, since this dump is in the middle of the W-cycle, I believe the time on the finest grid is different then the root grid. How do I find the time on the finest grid for this checkpoint dump? Thanks.

-- ------------------------------------------------------------------------ Joseph Smidt

Theoretical Division P.O. Box 1663, Mail Stop B283 Los Alamos, NM 87545 Office: 505-665-9752 Fax: 505-667-1931

-- ------------------------------------------------------------------------ Joseph Smidt

Theoretical Division P.O. Box 1663, Mail Stop B283 Los Alamos, NM 87545 Office: 505-665-9752 Fax: 505-667-1931

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