Allow calculation of CFL frequency in surface kernels #175
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…L computation which is done based on *surface* values of the phase space flux. However, the evaluation of the phase space flux inside the surfaces is an extremely costly endeavor, measured at upwards of 25% of the total update for gyrokinetics in 3x2v. Since the phase space flux has to be evaluated at surfaces anyway, we will implement a modification to hyper_dg which returns the CFL from the surface updates. This will be highly disruptive, as it will involve modification to a large percentage of our kernels (but mostly a search and replace). Basic idea implemented in hyper_dg (does not currently build)
…m the surface kernels. Return CFL frequency from GK surface kernels instead of volume. Code compiles on my mac, but haven't yet checked unit/reg tests (gkylcas d44142f304d7b0e8e9e263741250d763e537d076).
…nge (but they probably don't all check for recorrectness of kernels. Will check some g2 reg tests before PRing.
…previous commit (or maybe there hadn't been because I forgot to add new kernels) and I hadn't seen them. They are mostly related to inconsistent signatures. I made the following hack for now to get it working: L12 of zero/gkyl_dg_euler_pkpm.h I added moms, and L149-151 of zero/gkyl_dg_euler_pkpm_priv.h I added getching of moms. This may be incorrect, it's just a hack to get the system working. @JunoRavin will resolve conflicts later.
…s defined, eliminating the previous formula in favor of just taking the maximum absolute value over all quad points and left/right sides of a cell. Unfortunately it seems the time step has overall dropped by a factor of 1.5 (33%) still. Will explore a little more but wanna commit kernels for now.
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This goes with gkylcas PR 22 (ammarhakim/gkylcas#22).
Currently hyper_dg and all (DG) equation objects expect the calculation of the CFL frequency to take place in the volume kernel. We wish to allow gyrokinetics to compute the CFL rate in the surface kernels instead, because we are using surface quadrature values of the CFL rate and we already evaluate quad values of alpha there. So this eliminates the need to evaluate alpha at quad nodes a second time.
I checked the relevant unit tests and they pass. I also ran VM reg tests through g2 and they all pass; GK reg tests don't pass because our time step changed, but we have a more restrictive one now.
@ammarhakim you can review if you want, but please let @JunoRavin merge