[Meep-discuss] Question about using map to set up object with any shapes
Hi everyone: I refer to one of archives as below to build up the object: On Tue, 14 Nov 2006, Pascual Munoz Munoz wrote: > I've been looking to the 'loop' howto on the wiki, but I cannot manage > how to make a loop that makes a list of objects in different positions > and with different widths, depending on the loop variable. > > I've tried several things, the one making more sense to me (but not > working) is (not changing the width of the slices): > (set! geometry >(list >(make block (center 0 0) (size W L) >(material (make dielectric (index nde >(do ((x (* -1 Gp) (+ x 1))) ((> x Gp)) >(make block (center 0 (* x 0.12)) (size W 0.12) >(material (make dielectric (index > 1.0 ) ) ) A "do" loop does not return a list of objects, which is what you want to do here. To create a list, the easiest thing is to use "map". For example, (set! geometry (cons (make block (center 0 0) (size W L) (material (make dielectric (index nde (map (lambda (x) (make block (center 0 (* x 0.12)) (size W 0.12) (material (make dielectric (index 1.0) (arith-sequence (- Gp) 1 (round (+ (* 2 Gp) 1)) Of course, this does not change the width of the slices (they are all W), but neither does your example. You can easily substitute some arbitrary function of x here. (Note that (cons a B) prepends an element "a" to the list "B".) It works pretty well. But I found out within map, it can only make one object. If I want to make another object,i.e. different epsilon and shape but related to x, the previous one won't be executed but only the later. e.g.: ( map (lambda (x) (make block ) (make cylinder) ... the block won't be produced. can anyone give me any hint to build up more than two objects with any shape using map? Thank you very much! Adrian 想及時通知通訊錄裡的所有親朋好友好消息，就來 Yahoo!奇摩電子信箱發簡訊！ http://tw.mobile.yahoo.com/texts/mail.php ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
Re: [Meep-discuss] unwanted dispersive behavior?
I'm happy that I found the problem, but extremely embarassed at my mistake and how long it took me to find it. I mistakenly used index of refraction data in place of permittivity data. Maybe I should consider a career in the aerospace industry. Thanks again for your help. Best Regards, Matt On Wed, 27 Jun 2007, matt wrote: > > > That's not it. I set the resolution early in the script, and I'm able > to confirm via h5ls that increasing the resolution in the script > increases the size of problem. > > Best, > Matt > >> The problem turned out to be that they were calling (set! resolution ...) >> too late in the file. When you call add-flux to add a flux plane the >> fields are initialized and the resolution etc. is set; changing the >> resolution etc. after that point has no effect (unless you call >> reset-meep! or similar). Perhaps your problem is similar? >> > > ___ > meep-discuss mailing list > meep-discuss@ab-initio.mit.edu > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss > ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
Re: [Meep-discuss] unwanted dispersive behavior?
That's not it. I set the resolution early in the script, and I'm able to confirm via h5ls that increasing the resolution in the script increases the size of problem. Best, Matt > The problem turned out to be that they were calling (set! resolution ...) > too late in the file. When you call add-flux to add a flux plane the > fields are initialized and the resolution etc. is set; changing the > resolution etc. after that point has no effect (unless you call > reset-meep! or similar). Perhaps your problem is similar? > ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
Re: [Meep-discuss] unwanted dispersive behavior?
On Wed, 27 Jun 2007, matt wrote: > I'm solving a simple multilayer loss-free dielectric slab scattering problem, > for the case of normal incidence. > > The problem is simple enough that it can be solved analytically. The > analytic solution matches published results, so I have confidence in its > correctness. > > As you can see in the attached plot, the resonance in the reflectivity is > frequency shifted by about 10 percent, and the scaling isn't quite right. Hi Matt, The Meep solution should definitely converge to the exact result as you increase resolution etc. (In fact, transmission through a multilayer film is one of the test cases: see tests/bragg_transmission.cpp.) Someone posted with a similar problem in March - they were comparing the transmission through a thin film to the analytical formula, and weren't getting convergence: http://thread.gmane.org/gmane.comp.science.electromagnetism.meep.general/746 The problem turned out to be that they were calling (set! resolution ...) too late in the file. When you call add-flux to add a flux plane the fields are initialized and the resolution etc. is set; changing the resolution etc. after that point has no effect (unless you call reset-meep! or similar). Perhaps your problem is similar? Regards, Steven G. Johnson ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
[Meep-discuss] unwanted dispersive behavior?
Hello, I'm solving a simple multilayer loss-free dielectric slab scattering problem, for the case of normal incidence. The problem is simple enough that it can be solved analytically. The analytic solution matches published results, so I have confidence in its correctness. As you can see in the attached plot, the resonance in the reflectivity is frequency shifted by about 10 percent, and the scaling isn't quite right. The meep result doesn't change when I 1) increase the resolution 2) calculate over a more narrowband frequency range 3) increase pml thickness 4) increase spacing between scatterer and flux planes 5) increase spacing between source and flux planes/scatterer 6) set eps-averaging? to false 7) increase "decay-by" (and run the sim longer) 8) change the gaussian excitation center frequency 9) change the gaussian excitation cutoff 10) calculate reflectivity based on a flux point instead of a flux plane Just looking at the curve width make me think there's some kind of dispersive behavior, but I have no idea where it could be coming from. Any ideas? Best Regards, Matt compare.png Description: meep_vs_analytic ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
