Hi all, I'm trying to implement an error estimator based on residuals. And for a laplacian problem I need to have the laplacian of my unknown. So I have used "fe_val.get_function_laplacians". When I use Q1 FE on a square domain, my laplacian is 0 so that's great :) But, when I use a quarter of disk, my laplacian is no more 0.
It seems to me that DEAL compute hessian on the reference cell and then apply transformations to be on real cell. So I made a test : on my square domain I printed the hessian matrix, denoted by H, on each quadrature points and then I saw that it's not symetric, although diagonals terms are 0. A consequence of that is when there is a rotation (in the case of a quarter of disk) then trace(H)!=0 even if we use Q1 FE. Are you agree with me ? Best, Stephane Veys _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
