Hello I was wondering if there is a simple way to extract a matrix form for the RHS operator in maxwells equations. I was hoping to experiment with the IMEX-RK routine but that requires a matrix form the linear RHS operator. I found what I think may be an example of that in '[thesis-experiments.git] / 2009-11-maxwell-spectrum / max-spec.py’ but I just wanted to confirm with you that is indeed what you were doing in the build_mat function. And just for the sake of me really understanding, would you mind explaining a bit what exactly you did? It looks like you are generating a 'unit vector’ for a given degree of freedom (if we have a column vector of length N then we iterate over N and say all entries of the column vector is 0 except for the current iteration), plugging into your RHS function and then iterating. But I’m not totally sure if i understand why that would work. Thanks for the great code! very clean and fully featured