Cholla Prep

MHD Debugging

I spent some more time bug hunting and found that the instability only shows up when a number is not exactly expressible in binary. After discussin this with Evan they pointed out that it could just be an artifact of turning a 3D algorithm into a 1D algorithm. So instead of continueing bug hunting I’m going to switch to implementing MHD into Cholla.

Miscellaneous Cholla Prep

Switching to working on Cholla requires quite a bit of prep so here’s what I did this week:

• Cleaned up a few notes on the Hydro-Sandbox code so that it can be put away for awhile
• Submit account request for the ORNL supercomputer system
• Update my fork of Cholla
• Figure out how to access POWER9/V100 nodes at Pitt’s H2P cluster
• Update the modules I’m using on H2P and the POWER9 nodes
• Get Cholla to compile on H2P
• Get Cholla running on H2P in serial and parallel
• Meet with Damon to discuss testing schemes

Near future plans

• Check if I can get cholla to run with GPU-MPI on H2P
• Check if Cholla’s regression test is working and fix it if it isn’t
• Figure out how I want to do future tests in Cholla
• Learn CUDA
• Learn how Cholla works

Miscellaneous

• Research pair programming
• Present on 3.3-3.5 of Naab & Ostriker 2017