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Failed to evaluate variable Jacobian
Posted Apr 26, 2011, 3:06 p.m. EDT Heat Transfer & Phase Change, Chemical Reaction Engineering, Studies & Solvers Version 4.1 2 Replies
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I am running a coupled problem, where I am using the Physics Transport of Diluted Species, Heat Transfer as well as general PDEs.
I got an error message saying
Failed to evaluate variable Jacobian
- Variable: mod1.c
- Global scope
where c is the dependent variable for the transport module.
Following some posts here on this error message, I have checked all the variable definitions several times and made sure that they are not simple, like a, b...
Could anyone please give me some clue as what things I should look for for this kind of error?
Your response is much appreciated.
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COMSOL uses the Jacobian of all dependent variables to help the solver iterate.
So if you define your "c" in such a way that it might not be derivable at least once (i.e. but not only: step function, discontinuities ...) then you might get this error message, hope it helps ;)
--
Good luck
Ivar
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Thank you very much for the reply.
The c is the concentration, which is the dependent variable of the transport module. I don't seem to have something that is discontinuous....
This is like debugging and so frustrating.. hehe.