Discussion Forum

No one able to help me?

Hi

have you tried to generate 20 integrals of the inner solution and export them as a table, you have also table operations that integrate over the table values, and you can inverse the row-colums

But this does perhaps not allow to pick an item from each in integrate that.

via matlab you should be able though

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Good luck
Ivar

Hi Ivar,
first thanks very much for your response.
With the table approach you suggested I don't think I can solve the problem because inside the integrals I have a product of variables picked from two different outer solutions.

I have tried also with the Livelink for Matlab with no luck because basically the formalism there in order to define an integral is:

val=mphint(model,{'e1','e2',...},'Dataset','X','Outersolnum',Y,'Solnum',Z);

so, as you can see, I can define a specific Dataset with X, a specific Outer Solution with Y and a specific Inner Solution with Z (or eventually using with(...,...) in the expression field) but the problem remains because the expressions to be integrated MUST involve variables picked from the same Outer Solution.

So, to my understanding, there is no way to develop an integral of a product of two variables (it can be also the same quantity) picked from two different outer solutions in a Parametric Sweep Eigenvalue Analysis.

I hope I am wrong because it looks ridiculous that all the solutions and all the variables are stored for each inner and outer solution, but I can't just pick the ones I want to do some post-processing, not even with the Livelink.

Claudio

Hi

You have an interesting case there, and I see the potential use, but not the answer ;)

Have you tried to twickle "support" ? at least it could be considered as a "suggesion" for next release

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Good luck
Ivar

Hi Ivar,
yes I have been in contact with the support for the last 2 weeks and, apparently, no one is able to handle the situation.

I hope they are gonna come out with at least a workaround because it is really embarrassing that such a big software lacks very easy post-processing task like mine.

Hi

well the reason for matlab or java or... programming access, is really to deal with special cases, even if they look rather evident, now

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Good luck
Ivar

Were you able to solve your problem? I have to do the same thing, if you solved it, please tell me how.

I solved it manually following a different approach. COMSOL support is awful! I spent like 4-5 weeks between completely useless phone conversations and emails and at the end they just told me that what I was asking IS IMPOSSIBLE TO BE DONE IN COMSOL...and we are just talking about a very basic post-processing procedure. Apparently a "with" operator (already implemented in COMSOL but just for inner solutions) able to pick variables from two different outer solutions is really TOO MUCH!

Good luck!

After all this time, did anyone solve that? Can you describe the steps you did?



I have a similar problem, where my parametric solution is 225 times (outer solution).

I need to extract variables from different solutions, and integrate them.
Apparently I need comsol not to search from all the solutions. Executing any variant of the following command, keeps returning 225 numbers (all the same). Is any way to overcome that?


lala=mphint(model,' with(2,ec.Jx)-with(5,ec.Jx) ) * (with(12,ec.Jx)-with(25,ec.Jx)', 'edim',3, 'selection',2)
lala=mphint(model,' (with(2,ec.Jx)-with(5,ec.Jx) ) * (with(12,ec.Jx)-with(25,ec.Jx))', 'edim',3,'selection',2,'Outersolnum',1)
lala=mphint(model,' (with(2,ec.Jx)-with(5,ec.Jx) ) * (with(12,ec.Jx)-with(25,ec.Jx))', 'edim',3, 'selection',2,'Solnum',1)


P.S.
I did contact comsol, but support is very disappointing.

Good news: there is a solution. The answer is to use COMSOL MATLAB LiveLink. You extract all variables you need using the mphinterp() command (it interpolates some variable across a grid you give it). Then you perform whatever you need to do in MATLAB.

Bad news: you need MATLAB and Livelink, both of which cost a pretty penny, and you have to spend time writing the code.

Edit: It may also be possible to do this with the Physics Builder. In the end, no built-in way that I know of.

hi
can some one tell me hw to integrate two solutions from different modes

i have to do surface integration of normal electric field of frequency at w and 2w

Apparently in 5.2 (not verified earlier versions) you can compare two solutions from a parametric sweep using Join Data Sets:

www.comsol.co.in/blogs/solution-joining-parametric-eigenfrequency-time-dependent-problems/