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Estimating memory requirements, constraining memory usage

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Hi

I'm a new user to comsol trying to port my old abaqus models to comsol.

Trying to run my first model I run into the problem that all RAM memory gets consumed by the solver and then the system simply kills the program (at'least this is what thinks is happening as the output messages indicates that the program is killed). I'm a bit surprised as I have 128 GB RAM and the model consists of no more than 1138260 elements (quadratic serenipity) and it seems that comsol make use of 8 of the available 16 cores on my machine.

In abaqus I can get an estimate of the minimum RAM required to run a model as well as the RAM required to optimally run the model so I wonder if there are some similar functionality in comsol?

Similarly in abaqus I can configure the maximum ammount of RAM the software may use, is this possible in comsol?

If of importance I'm on a linux system trying to run the model in batch mode. The model uses the solid mechanics interface, a viscoleastic material, include spring foundations and is a time dependent study. The mesh is a mixture of quadrilaterals and tetrahedrals.


1 Reply Last Post 28 giu 2023, 15:59 GMT-4
Jim Freels mechanical side of nuclear engineering, multiphysics analysis, COMSOL specialist

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Posted: 1 year ago 28 giu 2023, 15:59 GMT-4

Supply sample model file with the error, and we might be able to diagnosis better. Are you using the default solver ? What solver is that ? If running out of memory, perhaps you are using the direct solver. Set log level in the solver settings to the maximum, and you will get memory requirements. If you run out of physical memory, COMSOL can be set to automatically switch to virtual memory (disk space) which dramatically slows the solution. If a large problem, suggest using iterative solver instead of direct solver, but COMSOL usually does this for you automatically.

Also, suggest trying a simpler problem to start to get used to the different system that COMSOL uses over ABAQUS. ABAQUS is not nearly as flexible and COMSOL gives you more options which can cause you to go down the wrong path. Try simple as possible, coarse mesh etc,, and go from there.

crawl before you walk, walk before you run ...

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James D. Freels, Ph.D., P.E.
Supply sample model file with the error, and we might be able to diagnosis better. Are you using the default solver ? What solver is that ? If running out of memory, perhaps you are using the direct solver. Set log level in the solver settings to the maximum, and you will get memory requirements. If you run out of physical memory, COMSOL can be set to automatically switch to virtual memory (disk space) which dramatically slows the solution. If a large problem, suggest using iterative solver instead of direct solver, but COMSOL usually does this for you automatically. Also, suggest trying a simpler problem to start to get used to the different system that COMSOL uses over ABAQUS. ABAQUS is not nearly as flexible and COMSOL gives you more options which can cause you to go down the wrong path. Try simple as possible, coarse mesh etc,, and go from there. crawl before you walk, walk before you run ...

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