Thanks, Steven. I am starting to get the point. Best regards,
Simon On Sun, Sep 2, 2012 at 9:29 AM, Steven G. Johnson <[email protected]>wrote: > > On Sep 1, 2012, at 8:55 PM, Simon Huskier wrote: > > >> > 1. For Bloch-periodic boundary condition, the usual way is setting the >> k-point and ensure-periodicity as following. >> > (set! k-point (vector3 0 0 0)) >> > (set! ensure-periodicity true) >> > But in the code, they set the k-point to (kx 0 0). >> > (set! k-point (vector3 kx 0 0)) >> > If I change the above kx to zero, then I will get a wrong picture of >> plane wave. >> >> I can't replicate your problem; with your code if I set theta=0 (hence >> kx=0) then the output looks fine. (Replied by Steven) > > > Thank you to clarify my questions, Steven. My problem is that keep theta > = pi/4, and only change kx to 0, and then the output looks not correct (I > copied the code after the message). According to the explanation on the > MEEP wiki page, there are two possible values for the k-point: false or > vector3. > > > > If theta=pi/4, that not consistent with kx=0. A planewave that is not at > normal incidence is not periodic. > > > *Are there any differences between (set! k-point (vector3 0 0 0)) and > (set! k-point (vector3 kx 0 0))? *Here, assume kx is not equal zero. > > > I'm not sure I understand your question. If kx is nonzero, then the > boundary conditions in the two cases are different. In the first case > (0,0,0), the boundaries are periodic, whereas in the second case (kx,0,0) > the fields differ from periodic by a phase shift in the x direction. > > (Also, for k-point = 0,0,0 the fields are purely real; as soon as you set > a nonzero kx then the fields everywhere are complex. But you can remove > this difference by setting force-complex-fields? to true.) > > --SGJ > > _______________________________________________ > meep-discuss mailing list > [email protected] > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss >
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