This PR generalizes the code which handles permittivity distributions that vary in one direction only. Previously, this was detected only where the variation is in the x or y direction. Now, it is detected regardless of the direction of variation, e.g. it need not be aligned with the basis vectors.
This PR generalizes the code which handles permittivity distributions that vary in one direction only. Previously, this was detected only where the variation is in the x or y direction. Now, it is detected regardless of the direction of variation, e.g. it need not be aligned with the basis vectors.