EigenValues-EigenVector for a SquareMatrix

Ste07 · October 2, 2021, 12:30

Good morning everyone,
I'm pretty new to OpenFOAM and I am writing some code lines in an application.
At some point a matrix is generated as a scalarSquareMatrix and I have the necessity to find its eigenvalues and eigenvectors.
Is there a way to do this?
(I am using the OpenFOAM6 version).

Thanks in advance

dlahaye · October 5, 2021, 13:29

This is not trivial as OpenFoam does not implement eigenvalues / eigenvector decompositions for its sparse matrices.

In a first approach it might be (?) easier to dump OpenFoam matrices to file, read them into Matlab, Python, Julia or whatever you prefer, and use tools that these packages provide.

Some background info is here https://www.linkedin.com/pulse/openf...omenico-lahaye and the references cited.

Good luck, Domenico.

mAlletto · October 6, 2021, 08:28

In the com version there are classes to compute eigenvalues and vectors https://www.openfoam.com/documentati...x.html#details

Maybe it is of help

October 2, 2021, 12:30	EigenValues-EigenVector for a SquareMatrix	#1
Ste07 New Member Stefano Riva Join Date: Dec 2020 Location: Milano Posts: 4 Rep Power: 5	Good morning everyone, I'm pretty new to OpenFOAM and I am writing some code lines in an application. At some point a matrix is generated as a scalarSquareMatrix and I have the necessity to find its eigenvalues and eigenvectors. Is there a way to do this? (I am using the OpenFOAM6 version). Thanks in advance

October 6, 2021, 08:28		#3
mAlletto Senior Member Michael Alletto Join Date: Jun 2018 Location: Bremen Posts: 615 Rep Power: 15	In the com version there are classes to compute eigenvalues and vectors https://www.openfoam.com/documentati...x.html#details Maybe it is of help dlahaye likes this.

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October 5, 2021, 13:29		#2
dlahaye Senior Member Domenico Lahaye Join Date: Dec 2013 Posts: 723 Blog Entries: 1 Rep Power: 17	This is not trivial as OpenFoam does not implement eigenvalues / eigenvector decompositions for its sparse matrices. In a first approach it might be (?) easier to dump OpenFoam matrices to file, read them into Matlab, Python, Julia or whatever you prefer, and use tools that these packages provide. Some background info is here https://www.linkedin.com/pulse/openf...omenico-lahaye and the references cited. Good luck, Domenico.