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Parameter estimation
Posted Apr 24, 2012, 9:26 p.m. EDT Studies & Solvers Version 5.2 6 Replies
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I want to determine one parameter k1, which is used over the entire domain. However, objective function values should be compared only at a boundary. According to the Optimization user manual, I think I need to use “least square objective" at a boundary and either “control variable field over the entire domain” or “global control variable”. When I try these, I get an error message of “Incorrect number of coordinates in least-squares objective”. Can I define an objective function at a boundary and use a control variable applied to the entire domain so that the control variable can be evaluated over the entire domain in COMSOL? In the attached model, the Optimization module is used in Study 2.
I contacted technical support and heard that they would post a model example in the future (unscheduled for now). If you know how to do it, please advise. I'd greatly appreciate your help!
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Hello Joo-Youp Lee
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Hello,
I want to determine one parameter k1, which is used over the entire domain. However, objective function values should be compared only at a boundary. According to the Optimization user manual, I think I need to use “least square objective" at a boundary and either “control variable field over the entire domain” or “global control variable”. When I try these, I get an error message of “Incorrect number of coordinates in least-squares objective”. Can I define an objective function at a boundary and use a control variable applied to the entire domain so that the control variable can be evaluated over the entire domain in COMSOL? In the attached model, the Optimization module is used in Study 2.
I contacted technical support and heard that they would post a model example in the future (unscheduled for now). If you know how to do it, please advise. I'd greatly appreciate your help!
Hi,
Did you manage to overcome this error? I get the exact same. Thanks
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Hello,
I was having the same problem, and found out the way to solve it. I was using the point least square objective, and I was selecting a point in the geometry and giving it the temperature (which was measured in the lab). Apparently it was not enough to click on the point of evaluation, it actually needed the coordinates for the point where the temp was measured, in my case, a whole set of zeroes for every time dependent data point my measurements had. This requires then to add Coordinate columns for x and y (my model is 2D) and assigned the a zeros column to those coordinate columns.
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Nat
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Thank you for your kind message with all the details. I also recently learned the technique from COMSOL tech support. When I first contacted them back in 2012, they did not reply. When I contacted them with a similar question several months ago, I could hear the same answer as yours.
I appreciate you kindly share what you learned.
Regards,
Joo-Youp
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Thank you so much. I get this problem also. I am going to give up until I see you reply. Thank you so much
Jiaqing
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You will need to add coordinate columns (1 for 1D, 2 for 2D and 3 for 3D) in the data file as well as in the Least square Objective interface (right click).