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MUMPS allocation factor increased

Posted Dec 5, 2021, 6:20 a.m. EST 4 Replies

Carl Xu
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Is this harmful and if so how to avoid it?

4 Replies Last Post Dec 26, 2021, 9:34 a.m. EST
Henrik Sönnerlind COMSOL Employee

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Posted: 3 years ago Dec 9, 2021, 8:43 a.m. EST

In itself, it is not harmful, more than that the factorization of the stiffness matrix is somewhat slower because of repeated reallocations of memory.

But in practice, this is almost always caused by an underlying problem in the physics, which makes the prediction of the structure of the system of equations problematic. For example, you often see this when there is severe ill-conditioning, or when there are excessive deformations in a solid mechanics problem (e.g elements turning inside out).

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Henrik Sönnerlind
COMSOL
In itself, it is not harmful, more than that the factorization of the stiffness matrix is somewhat slower because of repeated reallocations of memory. But in practice, this is almost always caused by an underlying problem in the physics, which makes the prediction of the structure of the system of equations problematic. For example, you often see this when there is severe ill-conditioning, or when there are excessive deformations in a solid mechanics problem (e.g elements turning inside out).
Carl Xu
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Posted: 3 years ago Dec 20, 2021, 3:43 a.m. EST
Updated: 3 years ago Dec 20, 2021, 3:48 a.m. EST

Thank you very much Dr Sönnerlind! But why is this warning together with that of inverted elements never seen in lower versions?

Thank you very much Dr Sönnerlind! But why is this warning together with that of inverted elements never seen in lower versions?
Henrik Sönnerlind COMSOL Employee

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Posted: 3 years ago Dec 20, 2021, 4:21 p.m. EST

Can you please elaborate the last question a bit more?

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Henrik Sönnerlind
COMSOL
Can you please elaborate the last question a bit more?
Carl Xu
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Posted: 3 years ago Dec 26, 2021, 9:34 a.m. EST

Can you please elaborate the last question a bit more?

In comsol versions 3.5, 4 etc, there's no such warning as inverted elements.

>Can you please elaborate the last question a bit more? In comsol versions 3.5, 4 etc, there's no such warning as inverted elements.

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