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sensitivity analysis: specifying the attribute of sensitivity solver

Posted 21 oct. 2010, 04:02 UTC−4 Version 4.2 2 Replies

Mohammad Chowdhury
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Dear all

I want to do sensitivity analysis of a time dependent problem in Comsol 4.0. I want to perform forward sensitivity analysis to evaluate the gradient of the state variable w.r.t global control variable i.e. parameter. But I can not specify the attribute of the sensitivity solver such as forward or adjoint sensitivity.

I have searched the documents. Those suggests that I can change the attribute of the sensitivity physics in its' settings window or in the solver options. However I have never seen any option in both places to do that.

Can somebody suggest me about the problem? I will be grateful.

Best Regards

Mahfuz
2 Replies Last Post 27 déc. 2011, 00:39 UTC−5
COMSOL Moderator

Hello Mohammad Chowdhury

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Sangamesh Deepak
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Posted: 1 decade ago 24 sept. 2011, 16:04 UTC−4
Here is how I could specify the sensitivity method.

In my problem, I use stationary solver. First, I added sensitivity as an additional physics to my model. After specifying objective function and control variables, I computed solution. Once a solution is computed, a relevant tree appears below solver configurations (Study 1 -> Solver Configurations). Down the tree, a right click on stationary solver 1 (Study -> Solver Configurations -> Solver 1 -> Stationary Solver 1) allows me to add sensitivity node to stationary solver 1. In this sensitivity node, the sensitivity method can be set as either forward or adjoint. An image file showing the tree is attached.

I guess, one can similarly set sensitivity method for transient solvers too.

Initially. I too was clueless on specifying sensitivity method. As a last resort, I made a small model in COMSOL 3.5a. Examination of this COMSOL 3.5a model in COMSOL 4.2 gave me the necessary clue.
Here is how I could specify the sensitivity method. In my problem, I use stationary solver. First, I added sensitivity as an additional physics to my model. After specifying objective function and control variables, I computed solution. Once a solution is computed, a relevant tree appears below solver configurations (Study 1 -> Solver Configurations). Down the tree, a right click on stationary solver 1 (Study -> Solver Configurations -> Solver 1 -> Stationary Solver 1) allows me to add sensitivity node to stationary solver 1. In this sensitivity node, the sensitivity method can be set as either forward or adjoint. An image file showing the tree is attached. I guess, one can similarly set sensitivity method for transient solvers too. Initially. I too was clueless on specifying sensitivity method. As a last resort, I made a small model in COMSOL 3.5a. Examination of this COMSOL 3.5a model in COMSOL 4.2 gave me the necessary clue.

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Gyeorye Lee
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Posted: 1 decade ago 27 déc. 2011, 00:39 UTC−5
thanks
It's very helpful.
thanks It's very helpful.

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