two questions related to DG

Hi Guosheng,

You are right, variable coefficients and curved elements (non-constant Jacobians) are treated the same way. Instead of solving with a mass matrix with coefficient rho, we apply a mass matrix with coefficient 1/rho. Everything is calculated on the fly without computing mass matrices. This trick is explained in this paper:

C Koutschan, C Lehrenfeld, J. Schöberl: Computer Algebra meets Finite Elements: an Efficient Implementation for Maxwell's Equations in: Numerical and Symbolic Scientific Computing: Progress and Prospects, Ulrich Langer and Peter Paule (ed.), pp. 105-122. 2011. Springer, Wien, arxiv.org/abs/1104.4208

Best,
Joachim

I see... very interesting! Thanks for the reference

This reminds me the low-storage DG or weight-adjusted DG method of Tim Warburton. Although he used a nodal basis...