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error 6250 with Piecewise Analytic Functions
Posted 23 dic 2010, 03:37 GMT-5 Heat Transfer & Phase Change, Materials, Studies & Solvers 2 Replies
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Hello,
I am using COMSOL 3.5 with the general heat transfers model.
I would like to impose an energy flow to a sub-domain, and this energy flow is function of time. Thus, I have written the polynomial equations of the flow in "options, functions, Piecewise Analytic Functions". The argument is t (time). The flux is cut into several equations during time.
But when I try to run the temporal model I have an error 6250 : Failed to evaluate variable jacobian. And the problem comes from the variable defined in “functions”
I have the same error with every equation I try, even the simplest (like f(t)=0 for 0<t<end). But when I write the same equation directly in the sub-domain, I have no error.
I guess the polynomial equations are correctly written because I can have a view of them when I press on “graph”.
As I try the model with simple equations, I don’t think the extrapolation or smoothing can help.
Where does my problem could come from?
Sincerely,
Anne-Maude Bazin
I am using COMSOL 3.5 with the general heat transfers model.
I would like to impose an energy flow to a sub-domain, and this energy flow is function of time. Thus, I have written the polynomial equations of the flow in "options, functions, Piecewise Analytic Functions". The argument is t (time). The flux is cut into several equations during time.
But when I try to run the temporal model I have an error 6250 : Failed to evaluate variable jacobian. And the problem comes from the variable defined in “functions”
I have the same error with every equation I try, even the simplest (like f(t)=0 for 0<t<end). But when I write the same equation directly in the sub-domain, I have no error.
I guess the polynomial equations are correctly written because I can have a view of them when I press on “graph”.
As I try the model with simple equations, I don’t think the extrapolation or smoothing can help.
Where does my problem could come from?
Sincerely,
Anne-Maude Bazin
2 Replies Last Post 8 mag 2012, 07:30 GMT-4
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Posted:
1 decade ago
Hi
I suspect its because your function is not smooth enough and the internal task to get the derivatives for the Jacobian are failing. I would suggest that you check your curve and perhaps smoothens it somewhat at the transition points. And/or play with the polynomial fit order, or both
--
Good luck
Ivar
I suspect its because your function is not smooth enough and the internal task to get the derivatives for the Jacobian are failing. I would suggest that you check your curve and perhaps smoothens it somewhat at the transition points. And/or play with the polynomial fit order, or both
--
Good luck
Ivar
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Posted:
1 decade ago
Hi!
did you manage to solve your problem? i am in the same situation and don't know what to do.
Thanks,
Roman.
did you manage to solve your problem? i am in the same situation and don't know what to do.
Thanks,
Roman.