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Memory issues

Posted Jul 28, 2010, 12:39 p.m. EDT 4 Replies

marina domokhovsky
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Hi, I am having memory issues. When I run my fluid structure interaction model, I run out of memory at about 20000 DOF during LU decomp or another error is "out of memory at stationary solver", however, when the structural module is used, its able to solve for 200K DOF. Any idea what it might be? I have a very old version of Comsol 3.3, so I dont think uploading it here would do any good. From another thread I understood that it might be the problem with BCs, however, when a coarse mesh is used, I am able to solve the problem.

Thanks for any help
Marina
4 Replies Last Post Aug 2, 2010, 3:39 p.m. EDT
marina domokhovsky
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Posted: 1 decade ago Jul 30, 2010, 10:56 a.m. EDT
Also, when I try to run the comsol tutorial (obstacle in fluid) my comp cannot solve it, even though it only has about 18000 DOF. Could it have something to so with the module used (fluid structure interaction)? Any help is appreciated.
Also, when I try to run the comsol tutorial (obstacle in fluid) my comp cannot solve it, even though it only has about 18000 DOF. Could it have something to so with the module used (fluid structure interaction)? Any help is appreciated.
Jim Freels mechanical side of nuclear engineering, multiphysics analysis, COMSOL specialist
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Posted: 1 decade ago Jul 30, 2010, 3:19 p.m. EDT
The more physics you have in a problem, and the more coupling between the physics, the larger the solution matrix and bandwidth of that matrix become. My guess is that you have exceeded the limits of your hardware. What kind of hardware and operation system are you using ?
The more physics you have in a problem, and the more coupling between the physics, the larger the solution matrix and bandwidth of that matrix become. My guess is that you have exceeded the limits of your hardware. What kind of hardware and operation system are you using ?
marina domokhovsky
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Posted: 1 decade ago Aug 2, 2010, 10:40 a.m. EDT
Hi, thank you for the reply, I think you are right. I am using windows XP and it has 2 GB. So, I might have better luck with 4 GB?
Hi, thank you for the reply, I think you are right. I am using windows XP and it has 2 GB. So, I might have better luck with 4 GB?
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Aug 2, 2010, 3:39 p.m. EDT
Hi

check the doc about DoF's (degrees of freedom) and hspae functions. I manage to saturate easily my 48GB if I'm not using some care, such as checking smmetry, removing unwanted details, using the required physics, checking mesh density ...

There is no one rule

--
Good luck
Ivar
Hi check the doc about DoF's (degrees of freedom) and hspae functions. I manage to saturate easily my 48GB if I'm not using some care, such as checking smmetry, removing unwanted details, using the required physics, checking mesh density ... There is no one rule -- Good luck Ivar

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