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Evaluate expression for different (specific) solutions

Posted Aug 26, 2013, 10:58 a.m. EDT Parameters, Variables, & Functions, Results & Visualization Version 4.3, Version 4.3a, Version 4.3b 3 Replies

Nikita Kondratiev
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Hi all.

Does anybody know how to evaluate expression for different solutions at the same time? I mean something like coupling integral between several modes. For example I have an eigenvalue problem solved and need to integrate the multiplication of the first one and the second (fourth and sixth, or whatever).

Thanks for help if any.
3 Replies Last Post Oct 4, 2013, 10:14 a.m. EDT
Jeff Hiller COMSOL Employee

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Posted: 1 decade ago Aug 26, 2013, 11:06 a.m. EDT
Hello,
The with() operator is probably what you are looking for. See the Reference Manual for details.
Best,
JF
Hello, The with() operator is probably what you are looking for. See the Reference Manual for details. Best, JF
Nikita Kondratiev
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Posted: 1 decade ago Aug 27, 2013, 3:23 a.m. EDT
Thanks for your reply.
The advice was helpfull, but didn't solve the whole problem: operator 'with' deals with the same solution. That is it works if you have one solution (following Comsol terminology) of an equation, with several eigenvalues and you want to compute coupling integrals. But I also need to do that for different solutions. Different dependent variables different equations and different parameters.
Operator 'with' seems like taking only number of eigenvalue as an argument, not a number of solution.
Thanks for your reply. The advice was helpfull, but didn't solve the whole problem: operator 'with' deals with the same solution. That is it works if you have one solution (following Comsol terminology) of an equation, with several eigenvalues and you want to compute coupling integrals. But I also need to do that for different solutions. Different dependent variables different equations and different parameters. Operator 'with' seems like taking only number of eigenvalue as an argument, not a number of solution.
Reine Granström COMSOL Employee

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Posted: 1 decade ago Oct 4, 2013, 10:14 a.m. EDT
Dear Nikita,

As stated in the documentation, the with operator can be used for time-dependent problems, parametric problems, and eigenvalue problems. We can use it to access the solution at any of the time steps, any parameter value, or any eigensolution in an expression used for plotting or data evaluation. Currently the with operator does not support inner and outer solutions, so for such models it can can not be used to access any combination of inner and outer solutions. For example, we can not use it if we have a parametric sweep (outer solution) for a time-dependent study (inner solution), or a parametric sweep (outer solution) for an eigenfrequency problem (inner solution).

Best regards,
Reine Granström
COMSOL Sweden
Dear Nikita, As stated in the documentation, the [b]with[/b] operator can be used for time-dependent problems, parametric problems, and eigenvalue problems. We can use it to access the solution at any of the time steps, any parameter value, or any eigensolution in an expression used for plotting or data evaluation. Currently the with operator does not support inner and outer solutions, so for such models it can can not be used to access any combination of inner and outer solutions. For example, we can not use it if we have a parametric sweep (outer solution) for a time-dependent study (inner solution), or a parametric sweep (outer solution) for an eigenfrequency problem (inner solution). Best regards, Reine Granström COMSOL Sweden

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