Re: [Meep-discuss] Complex field in meep
On Mar 7, 2009, at 10:51 PM, adrian wrote: If we go to meep reference page and see category: input variables we can find the explanation for force-complex-fields? Then we click : See also: Complex fields in Meep. the last sentence of the paragraph , the page popping up will show a message that you have to log in to edit. That's what I mean I have to log in. That means that the page doesn't exist yet; I was thinking of writing a more detailed discussion at some point, but haven't done so yet. Steven ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
Re: [Meep-discuss] Complex field in meep
Hi Zheng: I finally figure out your approach after reading one website as below: http://www.martinos.org/~adunn/papers/dissertation/node36.html I think that's what you mean. However, I am thinking if anyway in meep to accumulate the field in one period without storing fields in each time step for postprocess. Since if we have to do so, then it takes a huge disk space. so my question is: can we write a function in meep to sum up the field respect to time (or integrate field respect to time ) in one period and only output the accumulated field? Thanks a lot Cheers Adrian --- 09/3/6 (五)，Zheng Li lizhen...@mails.tsinghua.edu.cn 寫道： 寄件者: Zheng Li lizhen...@mails.tsinghua.edu.cn 主旨: Re: [Meep-discuss] Complex field in meep 收件者: adrian hiaquar...@yahoo.com.tw 日期: 2009 3 6 五 下午 4:17 Hi, adrian, You need to get fields' complex parts by yourself. 1, accumulate fields at every point of the surface you like for a period of time 2, retrieve what you want via applying FFT to the data in the time-domain. 3, apply spatial FFT to those complex number arrays. Yours Zheng 2009-3-6 adrian 写道: Hi Zheng: Thanks for your reply. However, if I'd like to use FFT then I need real part and imaginary part of the field and that's why I have to compute the complex field. What I try to figure out is if the definition of complex field is the same as what I said: E0*exp(j(wt-kr)) and real field I obtain is the real part of that formula and imaginary field is the imaginary part of the formula. If it is true, I may put the real field and imaginary field at one time step from meep into FFt formula to get Far field patterns. Thanks a lot Cheers Adrian --- 09/3/5 (四)，Zheng Li lizhen...@mails.tsinghua.edu.cn 寫道： 寄件者: Zheng Li lizhen...@mails.tsinghua.edu.cn 主旨: Re: [Meep-discuss] Complex field in meep 收件者: adrian hiaquar...@yahoo.com.tw 日期: 2009 3 5 四 下午 3:40 Hi, adrian, If you only simulate the dielectric structures, you needn't utilize complex fields because it may consume two-fold memory and CPU. Yet, if metals or other materials are involved, complex fields is the only choice to you. To complete the far-to-near field calculation, you might manipulate the obtained fields with FFT method in both of the time and spacial domains. Yours, Zheng 2009-3-5 adrian 写道: Hi Meep users and Steven: I know this question has been discussed but I can't find the answer to previous poster. My question is: 1. what is the definition of complex field in FDTD. Is it just E0*exp(j(wt - kr)) and the real field and imaginary field correspond to real part and imaginary part, respectively? If so, if we set force-complex-fields? false, then the real field we normally got is E0 times cos(wt - kr)? I try to reach Complex field in meep but it requires password. so I can't find the definition of complex fields in meep. The purpose for getting complex field is to get the far field patterns from the near field patterns calculated by meep Thanks in advanced Adrian 付費才容量無上限？Yahoo!奇摩電子信箱2.0免費給你，信件永遠不必刪！ - 馬 上體驗！ ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss 付費才容量無上限？Yahoo!奇摩電子信箱2.0免費給你，信件永遠不必刪！ - 馬 上體驗！ __ 付費才容量無上限？Yahoo!奇摩電子信箱2.0免費給你，信件永遠不必刪！ http://tw.mg0.mail.yahoo.com/dc/landing___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
Re: [Meep-discuss] Complex field in meep
Hi Zheng: I should make my question clearer. If I'd like to calculate the equation: sum Ex(r,t)*cos(w*t) over one period, can it be done in meep or I have to do postprocess, say to save field in each time step? Thanks Cheers Adrian --- 09/3/6 (五)，Zheng Li lizhen...@mails.tsinghua.edu.cn 寫道： 寄件者: Zheng Li lizhen...@mails.tsinghua.edu.cn 主旨: Re: [Meep-discuss] Complex field in meep 收件者: adrian hiaquar...@yahoo.com.tw 日期: 2009 3 6 五 下午 4:17 Hi, adrian, You need to get fields' complex parts by yourself. 1, accumulate fields at every point of the surface you like for a period of time 2, retrieve what you want via applying FFT to the data in the time-domain. 3, apply spatial FFT to those complex number arrays. Yours Zheng 2009-3-6 adrian 写道: Hi Zheng: Thanks for your reply. However, if I'd like to use FFT then I need real part and imaginary part of the field and that's why I have to compute the complex field. What I try to figure out is if the definition of complex field is the same as what I said: E0*exp(j(wt-kr)) and real field I obtain is the real part of that formula and imaginary field is the imaginary part of the formula. If it is true, I may put the real field and imaginary field at one time step from meep into FFt formula to get Far field patterns. Thanks a lot Cheers Adrian --- 09/3/5 (四)，Zheng Li lizhen...@mails.tsinghua.edu.cn 寫道： 寄件者: Zheng Li lizhen...@mails.tsinghua.edu.cn 主旨: Re: [Meep-discuss] Complex field in meep 收件者: adrian hiaquar...@yahoo.com.tw 日期: 2009 3 5 四 下午 3:40 Hi, adrian, If you only simulate the dielectric structures, you needn't utilize complex fields because it may consume two-fold memory and CPU. Yet, if metals or other materials are involved, complex fields is the only choice to you. To complete the far-to-near field calculation, you might manipulate the obtained fields with FFT method in both of the time and spacial domains. Yours, Zheng 2009-3-5 adrian 写道: Hi Meep users and Steven: I know this question has been discussed but I can't find the answer to previous poster. My question is: 1. what is the definition of complex field in FDTD. Is it just E0*exp(j(wt - kr)) and the real field and imaginary field correspond to real part and imaginary part, respectively? If so, if we set force-complex-fields? false, then the real field we normally got is E0 times cos(wt - kr)? I try to reach Complex field in meep but it requires password. so I can't find the definition of complex fields in meep. The purpose for getting complex field is to get the far field patterns from the near field patterns calculated by meep Thanks in advanced Adrian 付費才容量無上限？Yahoo!奇摩電子信箱2.0免費給你，信件永遠不必刪！ - 馬 上體驗！ ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss 付費才容量無上限？Yahoo!奇摩電子信箱2.0免費給你，信件永遠不必刪！ - 馬 上體驗！ __ 付費才容量無上限？Yahoo!奇摩電子信箱2.0免費給你，信件永遠不必刪！ http://tw.mg0.mail.yahoo.com/dc/landing___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
Re: [Meep-discuss] Complex field in meep
On Mar 6, 2009, at 4:31 PM, adrian wrote: Hi Zheng: I finally figure out your approach after reading one website as below: http://www.martinos.org/~adunn/papers/dissertation/node36.html I think that's what you mean. However, I am thinking if anyway in meep to accumulate the field in one period without storing fields in each time step for postprocess. Since if we have to do so, then it takes a huge disk space. so my question is: can we write a function in meep to sum up the field respect to time (or integrate field respect to time ) in one period and only output the accumulated field? If you want to accumulate the field at all points in space, the simplest way is to save it to a temporary file. You can delete each file after it is accumulated, so disk space is independent of run time. This has been discussed previously on the mailing list; see e.g. http://thread.gmane.org/gmane.comp.science.electromagnetism.meep.general/1455/focus=1456 Steven ___ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
