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Undefined value found in the equation residual vector.

Posted May 13, 2011, 2:05 p.m. EDT MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 5.2 23 Replies

Gulsah Ozisik
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I am trying to model a pem fuel cell. Although I have entered all parameters and values, i have some errors as follows;

Undefined value found.
- Detail: Undefined value found in the equation residual vector.
There are 4 degrees of freedom giving NaN/Inf in the vector for the variable mod1.wH2Oc
at coordinates: (0.0022813,0), (0.0022432,0), (0.0022813,7e-005), (0.0022432,7e-005), ...
There are 4 degrees of freedom giving NaN/Inf in the vector for the variable mod1.wO2
at coordinates: (0.0022813,0), (0.0022432,0), (0.0022813,7e-005), (0.0022432,7e-005), ...

Can you help me please?
23 Replies Last Post Jan 30, 2017, 4:25 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago May 13, 2011, 4:31 p.m. EDT
Hi

for me this typically indicateds that you do not have enough boundary conditions defined to get to a unique solution, go over you model again, and ask yourself if all dependent variables have enough BC's

--
Good luck
Ivar
Hi for me this typically indicateds that you do not have enough boundary conditions defined to get to a unique solution, go over you model again, and ask yourself if all dependent variables have enough BC's -- Good luck Ivar
Gulsah Ozisik
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Posted: 1 decade ago May 13, 2011, 5:35 p.m. EDT


When I used to average velocity instead of volumetric flow rate as boundary condition, it did not give error message and it solved.

Thanks your help
When I used to average velocity instead of volumetric flow rate as boundary condition, it did not give error message and it solved. Thanks your help
Saurabh Mittal
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Posted: 1 decade ago Dec 10, 2013, 11:36 p.m. EST
YES! it means not proper boundary conditions! Comsol always speaks in riddles!
YES! it means not proper boundary conditions! Comsol always speaks in riddles!
Dmitry Moiseev
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Posted: 1 decade ago Feb 3, 2014, 1:45 p.m. EST
I don't completely agree. I faced the same error while modeling semiconductor device. Boundary conditions are either insulating or metal that is enough to define dependent variables which are V - potential, n - electron density and p - hole density.
I don't completely agree. I faced the same error while modeling semiconductor device. Boundary conditions are either insulating or metal that is enough to define dependent variables which are V - potential, n - electron density and p - hole density.
Mahmoud Elzouka
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Posted: 1 decade ago Feb 16, 2014, 7:03 p.m. EST
How could you solve this problem? I mean you mentioned that you have the following message
"undefined values found in the equation residual vector" while defining proper BC for your semiconductor.
I really need your help!
How could you solve this problem? I mean you mentioned that you have the following message "undefined values found in the equation residual vector" while defining proper BC for your semiconductor. I really need your help!
Marwan Nafea
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Posted: 10 years ago Jul 14, 2014, 3:45 p.m. EDT
Hi all,

I just wanted to share a solution for this problem. It works in some cases.

I am not sure how your models look like, but I can tell you that one of the main reason behind this error is not have enough boundary conditions.

Another reason might cause this, and it happened to me, is the properties of the materials, such as the poisson's ratio. I kept getting the same error as the one you mentioned, although I set enough boundary conditions. Then, the problem was solved just by changing the poisson's ratio of PDMS from 0.5 to 0.49, and everything worked fine after that.

Best regards,
Marwan
Hi all, I just wanted to share a solution for this problem. It works in some cases. I am not sure how your models look like, but I can tell you that one of the main reason behind this error is not have enough boundary conditions. Another reason might cause this, and it happened to me, is the properties of the materials, such as the poisson's ratio. I kept getting the same error as the one you mentioned, although I set enough boundary conditions. Then, the problem was solved just by changing the poisson's ratio of PDMS from 0.5 to 0.49, and everything worked fine after that. Best regards, Marwan
Andrea Manconi
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Posted: 9 years ago Jan 13, 2015, 6:16 a.m. EST
I have experienced the same problem. By changing the Poisson's ratio to a lower value the model run.


Hi all,

I just wanted to share a solution for this problem. It works in some cases.

I am not sure how your models look like, but I can tell you that one of the main reason behind this error is not have enough boundary conditions.

Another reason might cause this, and it happened to me, is the properties of the materials, such as the poisson's ratio. I kept getting the same error as the one you mentioned, although I set enough boundary conditions. Then, the problem was solved just by changing the poisson's ratio of PDMS from 0.5 to 0.49, and everything worked fine after that.

Best regards,
Marwan


I have experienced the same problem. By changing the Poisson's ratio to a lower value the model run. [QUOTE] Hi all, I just wanted to share a solution for this problem. It works in some cases. I am not sure how your models look like, but I can tell you that one of the main reason behind this error is not have enough boundary conditions. Another reason might cause this, and it happened to me, is the properties of the materials, such as the poisson's ratio. I kept getting the same error as the one you mentioned, although I set enough boundary conditions. Then, the problem was solved just by changing the poisson's ratio of PDMS from 0.5 to 0.49, and everything worked fine after that. Best regards, Marwan [/QUOTE]
Charalampos Ferekidis
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Posted: 9 years ago Jan 23, 2015, 6:29 a.m. EST
I noted exactly the same behaviour when trying to solve an acoustic problem. One material had by accident a poisson ratio of 0.5 and I got the error "Undefined value found in the equation residual vector". However when changing the ratio to 0.49 everything was fine.


I have experienced the same problem. By changing the Poisson's ratio to a lower value the model run.


Hi all,

I just wanted to share a solution for this problem. It works in some cases.

I am not sure how your models look like, but I can tell you that one of the main reason behind this error is not have enough boundary conditions.

Another reason might cause this, and it happened to me, is the properties of the materials, such as the poisson's ratio. I kept getting the same error as the one you mentioned, although I set enough boundary conditions. Then, the problem was solved just by changing the poisson's ratio of PDMS from 0.5 to 0.49, and everything worked fine after that.

Best regards,
Marwan



I noted exactly the same behaviour when trying to solve an acoustic problem. One material had by accident a poisson ratio of 0.5 and I got the error "Undefined value found in the equation residual vector". However when changing the ratio to 0.49 everything was fine. [QUOTE] I have experienced the same problem. By changing the Poisson's ratio to a lower value the model run. [QUOTE] Hi all, I just wanted to share a solution for this problem. It works in some cases. I am not sure how your models look like, but I can tell you that one of the main reason behind this error is not have enough boundary conditions. Another reason might cause this, and it happened to me, is the properties of the materials, such as the poisson's ratio. I kept getting the same error as the one you mentioned, although I set enough boundary conditions. Then, the problem was solved just by changing the poisson's ratio of PDMS from 0.5 to 0.49, and everything worked fine after that. Best regards, Marwan [/QUOTE] [/QUOTE]
Kate
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Posted: 9 years ago Feb 6, 2015, 2:06 a.m. EST
Hi Ivar，
I saw you helped so many people. Thanks for your generous help. And could you help me with this premixed laminar combustion of hydrogen in a 2-D symmetric cylinder ?
I am using COMSOL to simulate steady state premixed laminar combustion of hydrogen (all mixture can be considered as ideal gas)in a cylinder with specific diameter to get the space dependent temperature and concentration distribution. So I coupled the laminar flow, heat transfer in flows and transport in diluted species(I am not sure whether it is proper to use this module for mass transport , to make it more reasonable, I assume the reactants ,i.e. the hydrogen and the oxygen are dissolved in nitrogen). But then I encountered the problem “Undefined value found in the equation residual vector”. I tried the methods you mentioned here but it seems they do not work. Could you help me with this？
I really appreciate your kind help.
Best,
Kate
Hi Ivar， I saw you helped so many people. Thanks for your generous help. And could you help me with this premixed laminar combustion of hydrogen in a 2-D symmetric cylinder ? I am using COMSOL to simulate steady state premixed laminar combustion of hydrogen (all mixture can be considered as ideal gas)in a cylinder with specific diameter to get the space dependent temperature and concentration distribution. So I coupled the laminar flow, heat transfer in flows and transport in diluted species(I am not sure whether it is proper to use this module for mass transport , to make it more reasonable, I assume the reactants ,i.e. the hydrogen and the oxygen are dissolved in nitrogen). But then I encountered the problem “Undefined value found in the equation residual vector”. I tried the methods you mentioned here but it seems they do not work. Could you help me with this？ I really appreciate your kind help. Best, Kate

Attachments:

Kaiwen Yuan
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Posted: 9 years ago Apr 2, 2015, 3:11 a.m. EDT
LOL
I exactly met same prob and solved it.

You guys must use PDMS, right? lollll.
LOL I exactly met same prob and solved it. You guys must use PDMS, right? lollll.
Kate
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Posted: 9 years ago Apr 2, 2015, 9:55 a.m. EDT
Hi, so you also work on combustion problem? I used the PARDISO solver for the steady-state simulation. so you mean this information? How should I change it?
Thanks for your help, Kaiwen.
Hi, so you also work on combustion problem? I used the PARDISO solver for the steady-state simulation. so you mean this information? How should I change it? Thanks for your help, Kaiwen.
Jordan Chase
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Posted: 9 years ago Apr 14, 2015, 5:10 p.m. EDT
I found the same issue in the Thermoelectric module and the issue was related to how the electrical conductivity was calculated.
All my properties are functions of T[K] and refer to tables... I initially tried to define the conductivity via the inverse equation of Rho(T) [Ohm*m], since I had tabulated data for Resistivity only. I called the inverse equation sig(T) [S/m] and experienced the error described above.
I went back to the material properties and instead defined Sigma as 1/Rho(T) and the issue disappeared.
Cheers
I found the same issue in the Thermoelectric module and the issue was related to how the electrical conductivity was calculated. All my properties are functions of T[K] and refer to tables... I initially tried to define the conductivity via the inverse equation of Rho(T) [Ohm*m], since I had tabulated data for Resistivity only. I called the inverse equation sig(T) [S/m] and experienced the error described above. I went back to the material properties and instead defined Sigma as 1/Rho(T) and the issue disappeared. Cheers
Fnu Kumar Vishal
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Posted: 9 years ago Apr 21, 2015, 6:26 p.m. EDT
Hi All,
I am getting this error in my non-reciprocal device. Material I used are (sio2, Al, PVDF) air, and ground.
I am getting this error:
Undefined value found.
- Detail: Undefined value found in the equation residual vector.
There are 1264294 degrees of freedom giving NaN/Inf in the vector for the variable comp1.E10.
at coordinates: (0.000359841,0.000300061,4.29763e-006), (0.000359837,0.000300122,4.24882e-006), (0.000359819,0.0003,4.29763e-006), (0.000359811,0.000300122,4.2e-006), (0.000359793,0.0003,4.24882e-006), ...
There are 934276 degrees of freedom giving NaN/Inf in the vector for the variable comp1.E20.
at coordinates: (0.000359815,0.000300061,4.24882e-006), (0.000359893,0.000300061,4.24882e-006), (0.000359871,0.0003,4.24882e-006), (0.000359867,0.000300061,4.2e-006), (0.00035975,0.0003,4.322e-006), ...
There are 934276 degrees of freedom giving NaN/Inf in the vector for the variable comp1.E21.
at coordinates: (0.000359815,0.000300061,4.24882e-006), (0.000359893,0.000300061,4.24882e-006), (0.000359871,0.0003,4.24882e-006), (0.000359867,0.000300061,4.2e-006), (0.00035975,0.0003,4.322e-006), ...

Can someone suggest me possible error in my structure.
It is attached here.

Hi All, I am getting this error in my non-reciprocal device. Material I used are (sio2, Al, PVDF) air, and ground. I am getting this error: Undefined value found. - Detail: Undefined value found in the equation residual vector. There are 1264294 degrees of freedom giving NaN/Inf in the vector for the variable comp1.E10. at coordinates: (0.000359841,0.000300061,4.29763e-006), (0.000359837,0.000300122,4.24882e-006), (0.000359819,0.0003,4.29763e-006), (0.000359811,0.000300122,4.2e-006), (0.000359793,0.0003,4.24882e-006), ... There are 934276 degrees of freedom giving NaN/Inf in the vector for the variable comp1.E20. at coordinates: (0.000359815,0.000300061,4.24882e-006), (0.000359893,0.000300061,4.24882e-006), (0.000359871,0.0003,4.24882e-006), (0.000359867,0.000300061,4.2e-006), (0.00035975,0.0003,4.322e-006), ... There are 934276 degrees of freedom giving NaN/Inf in the vector for the variable comp1.E21. at coordinates: (0.000359815,0.000300061,4.24882e-006), (0.000359893,0.000300061,4.24882e-006), (0.000359871,0.0003,4.24882e-006), (0.000359867,0.000300061,4.2e-006), (0.00035975,0.0003,4.322e-006), ... Can someone suggest me possible error in my structure. It is attached here.
Dong Fu
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Posted: 9 years ago May 6, 2015, 3:12 a.m. EDT
yes, I agree with you. However, sometimes I also meet the same problem when modeling semiconductor even I
have carefully made the boundary conditions. Have you met the same problem? and can you give me any suggestions for handling it?
Thanks!
yes, I agree with you. However, sometimes I also meet the same problem when modeling semiconductor even I have carefully made the boundary conditions. Have you met the same problem? and can you give me any suggestions for handling it? Thanks!
Markos Cardoso
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Posted: 9 years ago Aug 21, 2015, 12:02 p.m. EDT
Hi

I'm doing a kind of coupler with Si and SiO2 and comsol gives the same error when I try to simulate, could you tell me if you managed this error ?


Hi I'm doing a kind of coupler with Si and SiO2 and comsol gives the same error when I try to simulate, could you tell me if you managed this error ?
Kumar Vishal
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Posted: 9 years ago Aug 21, 2015, 12:15 p.m. EDT
Hi,
Sorry for delay, I have tried coarse mesh but it doesn't work then I tried to mesh with normal and it works good. I got the solution but I still have some questions because I didn't get the similar result as theoretical. I suggest try doing meshing very carefully.
Good luck!
Kumar
Hi, Sorry for delay, I have tried coarse mesh but it doesn't work then I tried to mesh with normal and it works good. I got the solution but I still have some questions because I didn't get the similar result as theoretical. I suggest try doing meshing very carefully. Good luck! Kumar
Salvador Magdaleno
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Posted: 8 years ago Apr 1, 2016, 3:24 p.m. EDT
Hi Charalampos

Thank you for your answer. I have a material with the same problem. I have defined a material with a poisson's ratio of 0.5 and I obtained the same error msg in Comsol.

I have changed the value of 0.5 to 0.49 and my model is running.

Salvador
Hi Charalampos Thank you for your answer. I have a material with the same problem. I have defined a material with a poisson's ratio of 0.5 and I obtained the same error msg in Comsol. I have changed the value of 0.5 to 0.49 and my model is running. Salvador
Salvador Magdaleno
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Posted: 8 years ago Apr 1, 2016, 3:27 p.m. EDT
yes the problem is the poisson's ratio in materials.
yes the problem is the poisson's ratio in materials.
Frank
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Posted: 8 years ago Aug 16, 2016, 9:59 p.m. EDT
I also met this error. But after my testing my model of electromagnetic waves, I got this fact that when my incident wavelength is lager than 600nm, my model can get proper results successfully, however, if the incident wavelength is smaller 600nm, like 55nm. the software would give this error. I am really confused why. Appreciate for your help if you could give me any advices, thank you!
I also met this error. But after my testing my model of electromagnetic waves, I got this fact that when my incident wavelength is lager than 600nm, my model can get proper results successfully, however, if the incident wavelength is smaller 600nm, like 55nm. the software would give this error. I am really confused why. Appreciate for your help if you could give me any advices, thank you!
David Zheng
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Posted: 8 years ago Aug 21, 2016, 7:21 a.m. EDT
hi， I happened to get the same question to yours. Have you solved it?
hi， I happened to get the same question to yours. Have you solved it?
Yang Zheng
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Posted: 7 years ago Nov 30, 2016, 8:47 p.m. EST
Hi

I just solved the error. It is because I didn't set a parameter properly(I forgot to set the speed of sound ).
Carefully check all your parameters, sometimes you might have accidently clicked user-defined parameters and the default value might be 0 and it will cause the error.

Hi I just solved the error. It is because I didn't set a parameter properly(I forgot to set the speed of sound ). Carefully check all your parameters, sometimes you might have accidently clicked user-defined parameters and the default value might be 0 and it will cause the error.
Mohamed Bahri
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Posted: 7 years ago Jan 30, 2017, 4:09 a.m. EST
Hi Fnu Kumar
I meet the same msg error when i tried to similate using the semi-conductor model
'''Undefined value found.
- Detail: Undefined value found in the equation residual vector.
There are 32 degrees of freedom giving NaN/Inf in the vector for the variable comp1.Ne.'''
I know that maybe you forget all this things? but please can you remember or give me any suggestions for handling it?
Thanks
Hi Fnu Kumar I meet the same msg error when i tried to similate using the semi-conductor model '''Undefined value found. - Detail: Undefined value found in the equation residual vector. There are 32 degrees of freedom giving NaN/Inf in the vector for the variable comp1.Ne.''' I know that maybe you forget all this things? but please can you remember or give me any suggestions for handling it? Thanks
Mohamed Bahri
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Posted: 7 years ago Jan 30, 2017, 4:25 a.m. EST
I meet the same msg error when i tried to similate using the semi-conductor model
'''Undefined value found.
- Detail: Undefined value found in the equation residual vector.
There are 32 degrees of freedom giving NaN/Inf in the vector for the variable comp1.Ne.'''
please can any one remember or give me any suggestions for handling it?
Thanks
I meet the same msg error when i tried to similate using the semi-conductor model '''Undefined value found. - Detail: Undefined value found in the equation residual vector. There are 32 degrees of freedom giving NaN/Inf in the vector for the variable comp1.Ne.''' please can any one remember or give me any suggestions for handling it? Thanks

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