Hello,
I am chasing a bug for my Navier-Stokes solver using Hdiv-HDG for a more than a week, and finally found out that for Hdiv-space, the correct way to calculate the gradient is using
instead of
This is a bit odd, as I am always using the lower-case grad operator... lol
So what's the difference???
Is there any documentation I can found on the source code on the implementation of differential operators?
This kind of bugs are extremely hard find as the lower case grad operator is also stable, but produce inaccurate results...
Best,
Guosheng