[Users] Meeting Minutes 2022-04-07

Gabella, William E b.gabella at Vanderbilt.Edu
Thu Apr 7 09:55:52 CDT 2022

Present:  Peter D, Bill G, Zach E, Yosef Z, Roland H, Atul K, Steve B,

Chair: Peter D, Minutes: Bill G

* next [https://docs.einsteintoolkit.org/et-docs/Release_Process ET 
[https://docs.einsteintoolkit.org/et-docs/Release_Details Details].

** The Kranc and NRPy+ codes, regeneration.  Roland, will check and run 
make (now).  Seems to be working, but with the Readme hash for NRPy+, so 
the older code.

Zach,  looking at WUThorns recently and Baikal has not been updated in a 
long time.  Core C code is the same, but different in the Python and 
Codegen side.  Also the automation of the CCL files has been improved.  
Because it take a long time for 8th order finite diff, it does a code 
gen in parallel, and Python's GIL does not allow parallelization easily, 
so NRPy clones itself, so when it is finished has to combine the 
results, uses Pickling. Zach found race conditions in the old version of 
Baikal that caused problems in the Codegen of Baikal and these have been 
remedied.  Zach, advocates for reviewing the new NRPy+ stuff.

Roland, we check regeneration just to see it works.  You should be able 
to regen it, if one wants.  So that if someone types to regen the code 
they get the latest versions.  Zach suggests to move on to the newer 
version.  A diff will show a lot of differences, Zach moved code between 
.h files to .c files, to speed up the compilation.  Does pass the 
unittests that were set up.  Zach is using the new version for BBHs, for 
his work.  The "new way" is the code to use; the "old way" is still there.

Zach can write instructions for testing.  Zach, new code is in NRPy+ 
master and in Jupyter notebooks.  Roland, but that is not what the 
Readme files say to do.  Zach, could convert the notebooks to Python 
files.  Roland, prefers if could cd in Baikal_ETK and it would build 
with a Makefile.  There is a one liner that runs the Jupyter by 
converting to Python and running.

Feature freeze is the 12th of April.

Decide on a name?  Those present voted for Bernhard Riemann as the name 
of the next release. https://en.wikipedia.org/wiki/Bernhard_Riemann

** Gallery, BBH?  Roland, no response from students, APS is in the way.  
Steve could do it, but better if students do it.  Steve, the BBH gallery 
is fairly will automated with Python scripts.

A little early to run the gallery examples.  Usual advice, if you have 
never run an example, do it soon.  And the run it again closer to and 
then after the Feature Freeze.

** FLRW Solver

Roland, has not tried to compile it, will do that.  Needs the Python C 
development files, which may or may not be present on certain clusters.  
Embeds Python interpreter in the compiled C code and runs preprocessed 
code.  It might also need some non-standard modules.  Python external 
library, maybe.  If so difficult, we do not want to include it this round.

[https://www.einsteintoolkit.org/tools/unanswered.php unanswered 
question on mailing list]

Garrison's post about Seg Fault  in CarpetReduce, when ghost zones set 
to 1 for reduction.  Roland will respond and ask again for a par file.

open tickets sorted by update time]

#2601  Add four parameters for carpet, Liwei has added six parameters 
with all x,y,z being treated ecumenically.

#2392  Roland, default values of keyword parameters not checked. 
Defaults for keywords were not set correctly, just taking the first one 
in a list.  Been around for 10+ years.  Steve does have fix for this at 
compiles time, is a pull request.  That does NOT close the ticket 
because of other issues.  Roland, should we keep the runtime checks?  If 
we have fixed the compiletime checks for these keyword parameters.  
Steve agrees do not need a runtime check for these...so maybe can close 
this ticket.  Steve, wants this PR in.  AHfinder is used without seeing 
the AHFinder bug. Roland, it is a level 3 or 4 warning.  AHFinder has 
the incorrect defaults; AHFinderDirect is fine, from Jonathan.

#2518  BlueGeneQ support?  Nothing done.

# 963  Improve McLachlan accuracy

#2589  Adding Kuibit to the tutorial server.  Also a Pull Request to 
update the server used for the tutorial server.  Steve and Roland have a 
discussion about the details.  Steve will try to review and get it in.

tickets ready for review]
# 2364 is an enhancement only, so not a big deal.

* Any other business

* Chairs / Minutes

April 14: Chair Roland, MInutes Atul

William Gabella
Research Assistant Professor
Department of Physics and Astronomy
Vanderbilt University
Nashville, TN  USA

b.gabella at vanderbilt.edu
(o) 615-343-2713

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