[yt-dev] Projection issues

[david collins]

Hi again--

I have another odd issue, again stemming from with this vintage
dataset.  It's a 512^3 root with 4 levels, and a refinement by 4.

When the parallel analysis gave me problems yesterday, I tried
re-griding the data by restarting and forcing parallel root grid io on
(including a removal of the rebuild hierarchy call to ensure the grids
stay the same, and returning before any hydro is done.)  The odd bit
is now projections look different.  Attached are two images,
sphere_serial is through the old serial  root grid run,
sphere_parallel is through the output with parallel root grid io.
Centered on the max, 0.02 in radius, Density projection.  Projections
were made using
proj = pf.h.proj(ax,field,center=center,source=sphere)  You can see
that less structure seems to be captured in the parallel dataset.

I've done two checks to make sure that it's not a glitch in the
re-griding.  First is the actual data-- the grids are in a different
order from parallel to serial, but once that's taken into account all
the data in subgrids is identical (at least in density, the field in
question).  Additionally the new tiles match the corresponding
positions in the old tile.  So the data itself is fine.

The other test I did was to regrid, but leaving serial root grid io
on-- new serial set is identical (except again for grid order) to the
old, and the projections match.

Differences also show up in profiles.

Again, not a major problem, but it's pretty counter-intuitive, so I
was wondering if anyone had run into this.

d.


-- 
Sent from my computer.
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