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Help : Problem facing in opening large file / out of memory processing

Posted Oct 29, 2012, 1:01 a.m. EDT Version 4.3 5 Replies

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I have my simulation file of size 1.5 GB where I am unable to see the results as it is showing "Out of mesh processing" when I am trying to see the plot ( 2D / 3D) etc.

Can anyone tell me the shortcut / alternative of doing the same.


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ishant.jain@tatasteel.com
5 Replies Last Post Oct 29, 2012, 5:27 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Oct 29, 2012, 2:29 a.m. EDT
Hi

I'm afraid you have the only solution to get hands on a more powerful PC with far more RAM.

Most reasonable complex engineering problems today require >32GB to solve in 3D if you start head on.

But you can make them significantly smaller by applying reasonable engineering physics, using symmetry, or 2D or bulk physics for given phenomena. This means you need to think a bit more and do some hand calculations, not just blindly trust the full model and COMSOL

I'm convinced, you can gain a lot of insight with 2GB RAM into many complex issues by decomposing a problem and studying the effects one by, one or two by two.

Having a powerful PC means you will get the nicest images, but it's no warrant that the results are "true", and it might take quite some time to get the results too ;)

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Good luck
Ivar
Hi I'm afraid you have the only solution to get hands on a more powerful PC with far more RAM. Most reasonable complex engineering problems today require >32GB to solve in 3D if you start head on. But you can make them significantly smaller by applying reasonable engineering physics, using symmetry, or 2D or bulk physics for given phenomena. This means you need to think a bit more and do some hand calculations, not just blindly trust the full model and COMSOL I'm convinced, you can gain a lot of insight with 2GB RAM into many complex issues by decomposing a problem and studying the effects one by, one or two by two. Having a powerful PC means you will get the nicest images, but it's no warrant that the results are "true", and it might take quite some time to get the results too ;) -- Good luck Ivar
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Posted: 1 decade ago Oct 29, 2012, 2:55 a.m. EDT
HI Ivar,
Thanks for your reply.

My problem is 3D based which I am solving in 2D axi model over cluster but having trouble to see the plots and other solution due to out of mesh processing error. The cluster computing get inactive once the simulation is complete.

Could you please suggest what can be done to see the result.

One more thing I have to add, Do we require to clear the previous solution every time if we are changing some minor boundary conditions ?
Rgrds,

Ishant

HI Ivar, Thanks for your reply. My problem is 3D based which I am solving in 2D axi model over cluster but having trouble to see the plots and other solution due to out of mesh processing error. The cluster computing get inactive once the simulation is complete. Could you please suggest what can be done to see the result. One more thing I have to add, Do we require to clear the previous solution every time if we are changing some minor boundary conditions ? Rgrds, Ishant
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Oct 29, 2012, 4:35 a.m. EDT
Hi

then you should not have any problem with RAM to solve ;)
But you might have to process the results on a "smaller" PC indeed !
Clusters are nice but how to transport the TB of data and to post process without the cluster ?

Clearing the previous solution, just as resetting the history makes the file smaller and resets the file (I often save and reopen the file if it's complex. Now I'm not sure what are the defaults when sending it to a cluster, as I have none.

Remains one issue: how does COMSOL restart = rerun when a solution already exist, i.e. if you solve once already, does it take initial values from initial value node or from previously solved case ? I'm not 100% sure, and as COMSOL is NOT logging where it takes its initial values from, in the solver log I cannot really tell.

Perhaps its worth to ask COMSOL support for that one
--
Good luck
Ivar
Hi then you should not have any problem with RAM to solve ;) But you might have to process the results on a "smaller" PC indeed ! Clusters are nice but how to transport the TB of data and to post process without the cluster ? Clearing the previous solution, just as resetting the history makes the file smaller and resets the file (I often save and reopen the file if it's complex. Now I'm not sure what are the defaults when sending it to a cluster, as I have none. Remains one issue: how does COMSOL restart = rerun when a solution already exist, i.e. if you solve once already, does it take initial values from initial value node or from previously solved case ? I'm not 100% sure, and as COMSOL is NOT logging where it takes its initial values from, in the solver log I cannot really tell. Perhaps its worth to ask COMSOL support for that one -- Good luck Ivar
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Posted: 1 decade ago Oct 29, 2012, 5:47 a.m. EDT

Yes, this is what I am looking for i.e. post processing the data without the cluster. I have used WINSCP to transfer the data from Cluster to PC.

Anyhow, If we can decrease the file size, then this can be possible over PC.

Also, could you please elaborate : " Clearing the previous solution, just as resetting the history makes the file smaller and resets the file (I often save and reopen the file if it's complex "


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Yes, this is what I am looking for i.e. post processing the data without the cluster. I have used WINSCP to transfer the data from Cluster to PC. Anyhow, If we can decrease the file size, then this can be possible over PC. Also, could you please elaborate : " Clearing the previous solution, just as resetting the history makes the file smaller and resets the file (I often save and reopen the file if it's complex " --
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Oct 29, 2012, 5:27 p.m. EDT
Hi

Nothing special there, it was just to ensure that you had discovered the "Edit Clear All Solution", "Edit Clear Mesh" and "File Reset History" options, that is a good method to reset your model to archive it (then it's small, or to upload it to the Forum)
After such a reset you should be sure you restart the solving process from new and from the original initial values

--
Good luck
Ivar
Hi Nothing special there, it was just to ensure that you had discovered the "Edit Clear All Solution", "Edit Clear Mesh" and "File Reset History" options, that is a good method to reset your model to archive it (then it's small, or to upload it to the Forum) After such a reset you should be sure you restart the solving process from new and from the original initial values -- Good luck Ivar

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