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circular variable dependency detected

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Hi,

The author of one paper has defined the conductivity as a function of current density and current density as a function of conductivity. In comsol, it gives a circular dependency error. How to get around it? I would appreciate any suggestion in this regard.

Regards,
Susant

4 Replies Last Post 4 giu 2017, 18:56 GMT-4
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Posted: 1 decade ago 11 ago 2014, 04:20 GMT-4
Hi,
I am having same problem. Have you solved the problem ?

Chandan Kumar
Hi, I am having same problem. Have you solved the problem ? Chandan Kumar

Nagi Elabbasi Facebook Reality Labs

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Posted: 1 decade ago 11 ago 2014, 10:48 GMT-4
There are two ways around this. If you can do some algebraic manipulations you may be able to get the conductivity and current density equations decoupled. If you cannot do that then define a new Domain ODE that breaks that circular dependency. The ODE can just involve one variable that you set equal to the current density and use that new variable in the definition of the conductivity.

Nagi Elabbasi
Veryst Engineering
There are two ways around this. If you can do some algebraic manipulations you may be able to get the conductivity and current density equations decoupled. If you cannot do that then define a new Domain ODE that breaks that circular dependency. The ODE can just involve one variable that you set equal to the current density and use that new variable in the definition of the conductivity. Nagi Elabbasi Veryst Engineering

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Posted: 8 years ago 12 giu 2016, 03:04 GMT-4
Hi,I am new to COMSOL. I had the same problem. Can you give a simple sample with second method(ODEs)? Thank you very much! My email is njutsjh@163.com.


Jianhua Shao
Hi,I am new to COMSOL. I had the same problem. Can you give a simple sample with second method(ODEs)? Thank you very much! My email is njutsjh@163.com. Jianhua Shao

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Posted: 7 years ago 4 giu 2017, 18:56 GMT-4
Hi,
I'm implementing a moving mesh in a 2D model with five dependent variables, imposing the 'prescribed deformation' in the domain with 'prescribed mesh displacement' dx = u1x and dy = u1y, but I get the following error message: circular variable dependency detected. Please, could you be more specific about the suggestion in your response of August 11 2014?
Thank you
Hi, I'm implementing a moving mesh in a 2D model with five dependent variables, imposing the 'prescribed deformation' in the domain with 'prescribed mesh displacement' dx = u1x and dy = u1y, but I get the following error message: circular variable dependency detected. Please, could you be more specific about the suggestion in your response of August 11 2014? Thank you

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