ERROR:: AddEquationSolution: > MG Levels < must be defined for geometric multigrid

Numerical methods and mathematical models of Elmer
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niranjan9ua
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ERROR:: AddEquationSolution: > MG Levels < must be defined for geometric multigrid

Post by niranjan9ua »

Hi Peter,

I downloaded files "ThermalFlowInCurvedPipe.zip" from "https://www.csc.fi/web/training/-/elmerfem_may2018". Files are from 23-24 May course this year.
When i run the model i got following error message
"ERROR:: AddEquationSolution: > MG Levels < must be defined for geometric multigrid!".

Could you please guide me how can i define "MG levels" as error is highlighted.

I am attaching solver log file for your reference.

Kind regards
Attachments
Solver-log.txt
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raback
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Re: ERROR:: AddEquationSolution: > MG Levels < must be defined for geometric multigrid

Post by raback »

Hi

Which of the files are you running? As far as I can see none of them uses geometric multigrid?

The keyword "MG Levels" is explained in ElmerSolver Manual.

-Peter
niranjan9ua
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Re: ERROR:: AddEquationSolution: > MG Levels < must be defined for geometric multigrid

Post by niranjan9ua »

Hi Peter,

All files attached here, did not change anything, I load the project and run it. all files are downloaded from the "ThermalFlowInCurvedPipe" or the link where you have uploaded course material "https://www.csc.fi/web/training/-/elmerfem_may2018".

Zip file includes the solver log files as well.



Regards
Attachments
ThermalFlowInCurvedPipe.zip
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raback
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Re: ERROR:: AddEquationSolution: > MG Levels < must be defined for geometric multigrid

Post by raback »

Hi

Rather than loading the project go to the project directory and simply call "ElmerSolver" on command line.

The project file is unfortunately version depedent. The sif file on the other hand is always backward compatible.

-Peter
CWeng
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Re: ERROR:: AddEquationSolution: > MG Levels < must be defined for geometric multigrid

Post by CWeng »

Hi,
I saw you use the following preconditioner in your .sif file
"Linear System Preconditioning = Multigrid"

You may try to either provide the multigrid level, or simply change the preconditioner to
"Linear System Preconditioning = ILUT"


-Chenyang
Best regards,
C. Weng
jeromiglopez
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Re: ERROR:: AddEquationSolution: > MG Levels < must be defined for geometric multigrid

Post by jeromiglopez »

CWeng wrote: 04 Sep 2019, 18:53 Hi,
I saw you use the following preconditioner in your .sif file
"Linear System Preconditioning = Multigrid"

You may try to either provide the multigrid level, or simply change the preconditioner to
"Linear System Preconditioning = ILUT"


-Chenyang
Thanks Chenyang! Changing from Multigrid to ILUT worked for me.
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