Hi Helmut, We do allow for variable coefficients in the mass matrix and stiff ness matrices setup. This is a feature which we have mainly used in 2D with manifold problems for atrial arthymia modelling. I am therefore cc’ing your question to Chris to see if he would comment on an example of how this is setup and whether it has been tested in 1D. Best regards, Spencer. On 3 Feb 2016, at 15:35, Kühnelt Helmut <Helmut.Kuehnelt@ait.ac.at<mailto:Helmut.Kuehnelt@ait.ac.at>> wrote: Dear Spencer, How can I implement or modify the EulerCFE code (only 1D is needed) to obtain a variant with mass and stiffness matrices with variable coefficients (i.e. M_A = \int_{-1}^{1} L_q L_p A(\xi,t) d\xi), as well as setting up similar matrices with variable coefficients for setting up source terms (e.g. M_s S_p). Best regards, Helmut _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk<mailto:Nektar-users@imperial.ac.uk> https://mailman.ic.ac.uk/mailman/listinfo/nektar-users Spencer Sherwin McLaren Racing/Royal Academy of Engineering Research Chair, Professor of Computational Fluid Mechanics, Department of Aeronautics, Imperial College London South Kensington Campus London SW7 2AZ s.sherwin@imperial.ac.uk<mailto:s.sherwin@imperial.ac.uk> +44 (0) 20 759 45052