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accessing the conductivity parameter
Posted 2009/07/23 17:57 GMT-4 3 Replies
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I am new to COMSOL, trying to use it as a forward solver for an optimization problem in the Matlab environment. I have looked at all the manuals and read all the sections I think are relevant. I am stuck. I want to be able to specify the conductivity of a subdomain externally, letting it vary during the optimization process, but cannot figure out how to find it in the fem structure.
I am hoping to use Matlab's own optimization routines, not the COMSOL Optimization Module, becasue 1) I will have more flexibility and 2) I cannot figure out how to bring out the conductiviy as a variable in the Optimization Module
I am hoping to use Matlab's own optimization routines, not the COMSOL Optimization Module, becasue 1) I will have more flexibility and 2) I cannot figure out how to bring out the conductiviy as a variable in the Optimization Module
3 Replies Last Post 2009/07/27 11:49 GMT-4
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Posted:
2 decades ago
An update: I exported my model as an M-file, and found out where the conductivity was set (equ.sigma). I tried to very it in a for loop, but got inconsistent results. Then I include more of the M-file in the for loop and still got inconsistent results. Finally I went back to the first versioono without a loop and manually changed the conductivity in one subdomain - still inconsistent!. ANy ideas?
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Posted:
2 decades ago
Hi
I cannot open your model because you have most probably done a "reset model", then COMSOL (for "complex" geometry but this definition is internal to COMSOL) mostly saves the geometry separately, see your line:
flbinaryfile='circ3_1inc.mphm';
so pls add this file (perhaps there are others too), else it is tough for us others to understand, I'm still no that fluent in COMSOl internals with out any geoemtry ;)
To start with matlab/script and COMSOL, really do simple task, run a few (4-5) examples from the doc so you get used to the approach, dont give up, I remember I was very frustatrated in the beginning, but once you got the trick you'll love it.
Good luck
Ivar
I cannot open your model because you have most probably done a "reset model", then COMSOL (for "complex" geometry but this definition is internal to COMSOL) mostly saves the geometry separately, see your line:
flbinaryfile='circ3_1inc.mphm';
so pls add this file (perhaps there are others too), else it is tough for us others to understand, I'm still no that fluent in COMSOl internals with out any geoemtry ;)
To start with matlab/script and COMSOL, really do simple task, run a few (4-5) examples from the doc so you get used to the approach, dont give up, I remember I was very frustatrated in the beginning, but once you got the trick you'll love it.
Good luck
Ivar
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Posted:
2 decades ago
Place the for loop in the beginning of your m-file. Put your variable inside the equ.sigma definition.
Example:
conduct = [0.001 0.01 0.1 1 10 100 1000];
for o = 1:length(conduct)
cond = conduct(o)
<- beginning of COMSOl m-file ->
...
clear equ
equ.sigma = {1.11,cond,3.33,4.44};
equ.ind = [1,2,3,4];
appl.equ = equ;
...
<- end of COMSOl m-file ->
end
That worked for me.
Greetz,
Maarten.
Example:
conduct = [0.001 0.01 0.1 1 10 100 1000];
for o = 1:length(conduct)
cond = conduct(o)
<- beginning of COMSOl m-file ->
...
clear equ
equ.sigma = {1.11,cond,3.33,4.44};
equ.ind = [1,2,3,4];
appl.equ = equ;
...
<- end of COMSOl m-file ->
end
That worked for me.
Greetz,
Maarten.