[3p3c] calculate densities in flux variables
The densities at the face are only set to zero. Calculate them by standard interpolation analogous to 2p2c. This fixes the calculation of diffusive fluxes in the local residual.
Fixes #457 (closed).
The densities at the face are only set to zero. Calculate them by standard interpolation analogous to 2p2c. This fixes the calculation of diffusive fluxes in the local residual.
Fixes #457 (closed).