COMSOL - parameter dependent eigenvalue calculations

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Discussion Overview

The discussion revolves around using COMSOL's RF module for parameter-dependent eigenvalue calculations related to optical fibers. Participants explore methods to automate the process of changing parameters, such as wavelength, and calculating eigenvalues without manual intervention.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant expresses frustration with manually changing parameters in COMSOL and seeks advice on automating the process using scripts or MATLAB.
  • Another participant suggests that using an m-file or COMSOL script model could be a general approach for automation.
  • A participant questions whether the parametric solver could be utilized for their problem, considering the need for continuous eigenvalue calculations.
  • There is a suggestion that the "parametric sweep" option in the eigenvalue solver might facilitate the desired calculations, although the participant has not used it for eigenvalue problems specifically.
  • DJ_GoodNews indicates difficulty finding the "parametric sweep" option in their version of COMSOL and questions if version differences might be a factor.
  • Another participant speculates that the "parametric sweep" feature may be a new addition in a later version of COMSOL, suggesting that version 3.4.0.250 might lack this functionality.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best approach to automate eigenvalue calculations, with multiple suggestions and uncertainties about the capabilities of different COMSOL versions.

Contextual Notes

Limitations include uncertainty about the availability of features in different versions of COMSOL, and the need for further clarification on how to effectively combine the parametric solver with the eigenvalue solver.

DJ_GoodNews
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Hello,

I am using COMSOL (RF modul) for some time now to calculate the eigenvalues (modes) of optical fibers. So far I changed all the params from hand in the software.

But it is getting anoying to change a parameter (the wavelength) and to recalculate if one wants to calculate for many parameters. Later one I want also to chage structural parameters of the microstructured fibers.

This means I have to use the skript or MATLAB to impelment loops and so, rigth?
But I have problems getting started. I get always errors and I do not know how to change the postprocessing correspondingly (so that I get all the wavelegth dependent calculated modes).

Does anyone have a hit? Are there good tutorials? Has anyone a example m-file for s.th. like this?

Thanks!

DJ_GoodNews.
 
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An m-file (or a comsol script model) would be the most general approach, but thinking about the easiest way have you thought whether the parametric solver would work for your problem?
 
Hello,

PerennialII said:
An m-file (or a comsol script model) would be the most general approach, but thinking about the easiest way have you thought whether the parametric solver would work for your problem?

I was thinking about that, but the problem is that I have to calculate the Eigenvalues all the time. Is it possible that the parametric solver and the eigenvalue solver work together? How do I manage that (without a skript)?

Cheers!
DJ_GoodNews.
 
...I think it might work straight up if you use the "parametric sweep" option for eigenvalue solver (under solve menu). Haven't used it for eigenvalue problems, but at least it's general enough to work for transient problems with the time dependent solver (so at least it's not solely for stationary problems).
 
PerennialII said:
...I think it might work straight up if you use the "parametric sweep" option for eigenvalue solver (under solve menu). Haven't used it for eigenvalue problems, but at least it's general enough to work for transient problems with the time dependent solver (so at least it's not solely for stationary problems).


Hi,

thanks for answering. But I do not find this "parametric sweep" option in the solve menu...
I use the Version COMSOL 3.4.0.250 is this a problem?

Cheers,
DJ-GoodNews
 
Yeah, could be. I'm not 100% sure but it may be one of the new features of release 3.5. Or at least don't remember seeing it earlier.
 

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