Eigenmode source calculated at wrong position in 3D

[ghost]

Hi everybody,

when I have a 3d geometry of a straight waveguide, parallel to the z-direction and I use the eigenmode-source on one side, I get the correct eigenmode there and thus the correct propagation through the waveguide.
Anyway, when I taper the waveguide for example and again use the eigenmode source at one end of the waveguide, I do not get the correct eigenmode! After testing I found out, that the eigenmode is always calculated in the z-center. Means: Even if I place the eigenmode source at one end of the waveguide, let's say (center 0 0 14) (size sx sy 0), the eigenmode is calculated at (center 0 0 0) (size sx sy 0).
Not even the (eig-lattice-center 0 0 14) (eig-lattice-size sx sy 0) commands can change this.

Can somebody confirm this bug?

Best regards
Marc

[stevengj]

Looks like this is a typo in mpb/src/mpb.cpp. Can you tell me whether the following patch fixes the problem?

--- a/src/mpb.cpp
+++ b/src/mpb.cpp
@@ -46,7 +46,7 @@ static void meep_mpb_eps(symmetric_matrix *eps,
   const double *s = eps_data->s;
   const double *o = eps_data->o;
   vec p(eps_data->dim == D3 ?
-       vec(o[0] + r[0] * s[0], o[1] + r[1] * s[1], o[1] + r[1] * s[1]) :
+       vec(o[0] + r[0] * s[0], o[1] + r[1] * s[1], o[2] + r[2] * s[2]) :
        (eps_data->dim == D2 ?
         vec(o[0] + r[0] * s[0], o[1] + r[1] * s[1]) :
         /* D1 */ vec(o[2] + r[2] * s[2])));

[ghost]

It does fix the problem.
As I can see, you already implemented the patch correctly. As it is actually MEEP/src/mpb.cpp
and

Thanks alot and best regards from Zurich
Marc