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optimization for transient problem (get optimized parameters for the model to fit the experiments)
Posted Mar 25, 2011, 10:26 a.m. EDT Version 4.0a 2 Replies
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Hi!
I have a model with several parameters say A, B, C, D, then run a transient analysis.
I want the results (a result vary with time) from the model to follow the data from an experiment,
in order to find the most optimized parameters that will fit the experiment.
Is this possible to do in Comsol ?
Thanks a lot.
XLi
I have a model with several parameters say A, B, C, D, then run a transient analysis.
I want the results (a result vary with time) from the model to follow the data from an experiment,
in order to find the most optimized parameters that will fit the experiment.
Is this possible to do in Comsol ?
Thanks a lot.
XLi
2 Replies Last Post Mar 26, 2011, 6:24 p.m. EDT
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Posted:
1 decade ago
Hi
define an ODE equation or Global equation and arrange your formula to be = 0
i.e. you define a variable that COMSOL adapts to get the equation to fit, its the poor mans optimisation, but you are correct, the optimisation module has all this in readily set up, and pre-cooked for you
--
Good luck
Ivar
define an ODE equation or Global equation and arrange your formula to be = 0
i.e. you define a variable that COMSOL adapts to get the equation to fit, its the poor mans optimisation, but you are correct, the optimisation module has all this in readily set up, and pre-cooked for you
--
Good luck
Ivar
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Posted:
1 decade ago
Hi Ivar,
I don't think this optimization in a timedependent model would be that easy. These days I am working on a curvefitting problem in COMSOL 4.0a. I use time dependent Nernst-Plank model. Using this model I am able to find the trend of current versus time and I have experimental trend as well. The plan is using the COMSOL model and the experimental results to find an optimum value for a physical constant. So the control variable is not changing through time. I also defined the objective variable as the integral of the RMS error between model and experimental results through time.
COMSOL all the time gives "singular matrix" error for the optimization of this problem. I found other people in this forum or in other places have the same problem.
Do you think using optimization module in a time dependent problem is beyond the capability of COMSOL and I need to optimize my problem using optimization toolbar in MATLAB? If this is the case do you know any example that can help me. I can't figure out how I should use optimization toolbar in this case.
I also posted a separate question about this to see the opinion of other people.
I greatly appericiate your help.
Atieh
I don't think this optimization in a timedependent model would be that easy. These days I am working on a curvefitting problem in COMSOL 4.0a. I use time dependent Nernst-Plank model. Using this model I am able to find the trend of current versus time and I have experimental trend as well. The plan is using the COMSOL model and the experimental results to find an optimum value for a physical constant. So the control variable is not changing through time. I also defined the objective variable as the integral of the RMS error between model and experimental results through time.
COMSOL all the time gives "singular matrix" error for the optimization of this problem. I found other people in this forum or in other places have the same problem.
Do you think using optimization module in a time dependent problem is beyond the capability of COMSOL and I need to optimize my problem using optimization toolbar in MATLAB? If this is the case do you know any example that can help me. I can't figure out how I should use optimization toolbar in this case.
I also posted a separate question about this to see the opinion of other people.
I greatly appericiate your help.
Atieh