[Users] Meeting Minutes for 2020-01-09
rhaas at illinois.edu
Thu Jan 9 11:33:28 CST 2020
while I was not in time to actually prepare these before the call, this:
are some slides outlining the current CarpetX status.
> Present: Liu Haoyang, Zhao Zhi-Chao, Bill Gabella, Zach Etienne, Steve Brandt, Roland Haas
> Chair: Steve
> Minutes: Bill
> * ETK Workshop at LSU in August 2020.
> o Likely August 3-7, the first week. Let Steve know what you would like to see there. Planning on student tutorial, will have students from LSU.
> o Some money for travel support---if you have a student you want to send ask Steve.
> o NRPy tutorial would be nice---Zach agrees. NRPy spreading around China; Zach back from a recent visit there.
> * Any information about an ETK workshop in Europe? Need to know and coordinate schedules.
> * Working group update: Performance Optimization AMRex
> o AMRex work with Erik and Steve. AMRex is a mesh refinement library developed by the DoE specifically by LBNL in California. Built-in support
> for tiling and multi-threading. Erik, Steve, and Roland, try to use AMRex as an underlying driver for Cactus. Have wave equation working. Roland
> visited Erik for a week over break, mesh-refinement code in there, and Zach's Baikal BSSN code that can evolve Minkowski ST without failing.
> And can do Schwarzschild BH with two puncture, until it fails. Likely the boundary conditions are wrong. Using two punctures as initial data.
> Is a Cactus thorn. Looping over grid points is different, so not backward compatible. Developed as a hydro code. Supports two kinds of variables,
> cell-centered and vertex-centered, which is not supported in Cactus at all. Metric is vertex-centered. AMRex uses the PreSync infrastructure of
> the Cactus branch Steve has been working on. Code is public. Repo cactusamrex in Erik's account (see below). Is the docker file Erik uses for
> testing. Need latest version of cmake. Erik is working on BCs other than periodic, Dirichlet and Reflection. Is a work in progress, but at a point
> where we can take Minkowski or Schwarzschild ST and run on a cluster and see how the framework scales---effects on run speed, etc. All
> refinements are on the same time step.
> o For Minkowski ST when evolve quantities 0 or 1 at least it does not die, but not sure if it is still 0 or 1, responding to Steve's question.
> o Took Zach's notebook and re-wrote the glue for it to work. Kept the physics the same.
> o Links:
> o Zach suggested a trumpet BH solution with corresponding gauge conditions, guaranteed to be static ST, and is a good test. Also numerically
> stable; shows up in the original NRPy paper.
> * Steve wants to get rid of cactuscode.org and make it a web page on ETK website. Should have an example web page for next week.
> * Next release, 6 months from late October, so maybe April.
> o Volunteer for heading the release needs to be determined.
> * Roland has some bug fixes to back port to the release.
> o System topology thorn will fail if using new (2.X) of hwloc library. Small change to the search.
> o In the ticketing system with "backports" in the subject. He would like to do this. Steve will look at the tickets and commits.
> o Maybe some updates for simfactory machines, but those get updated all the time.
> [edited for readability-my paragraph (non)wrapping looked like hell on lists.einsteintoolkit.org, finally put in hard breaks with shift-return
> in Thunderbird, bill]
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