Classes and Bugfixing 2

Astronomical Techniques

Started discussing statistics (the things not the subject) and I fixed some issues with the homework from last week. Overall uneventful

Numerical MHD

More bug hunting this week. I’ve hammered out most of the HLLD solver, all that’s left is 50-100 lines in the double star state computations. The wavespeeds, L/R, and L/R star states are all debugged along with most of the utility functions. Throughout this I’ve only found 1 bug, a simple typo in which variable to use. Out of a couple hundred lines of code I think that’s pretty good.

I’ve also been experimenting with some new debugging methods. Mostly that of using a jupyter notebook to help with comparing calculations. It actually works really well and is something I’ll have to continue doing. I’ve also been using the debugger to edit values in memory to help with debugging. Specifically editing the position over timer variable so that I can force the HLLD solver into any state I want and don’t have to fiddle with the initial conditions to make it happen. This has significantly sped up debugging and it something I will have to remember when I’m debugging Cholla’s future HLLD solver.

Other

• Watched Peng Oh’s keynote from KITP on the role of non-thermal physics in CGM evolution
• Attended the San Diego Super Computer Center’s webinar on optimizing your code. It was really good, if short, and you should be able to find it here when they post it.
• Started reading Essential magnetohydrodynamics for astrophysics by H. Spruit. It’s a review article on astrophysical MHD that is regularly updated. I’m reading version 3.5.1 from 2017 as that is the most recent version at the time of writing