Solve Ax=b

Rutger · August 8, 2015, 06:19

Hi,

I searched the forum but couldn't find a similar problem respectively an answer.
I'm running a simulation that stores its results in a volScalarField b ∈ R^n and a volVectorField A ∈ R^{nxn}.
The mathematically relation between them is A*x = b, which I want to solve for x. In another project I used a solver from the Eigen libary but now I want to calculate it in OpenFOAM.

It is possible to solve this linear equation or do I need to use a fvMatrix type for A ?

Rutger · August 10, 2015, 05:44

For everyone with the same problem:

The example in application/test/Matrix/Test-Matrix.C helped a lot. Now I'm copying the values from the vol*Field to the corresponding datatypes and solve the system.

Tushar@cfd · August 10, 2015, 10:13

Dear Rutger,

Have a look to the eigen value solver given in Tensor.C file. I think this will help you.

-
Best Luck!

Rutger · August 13, 2015, 08:26

Thanks, I will have a look at it.

August 8, 2015, 06:19	Solve Ax=b	#1
Rutger New Member Join Date: Aug 2015 Posts: 4 Rep Power: 11	Hi, I searched the forum but couldn't find a similar problem respectively an answer. I'm running a simulation that stores its results in a volScalarField b ∈ R^n and a volVectorField A ∈ R^{nxn}. The mathematically relation between them is A*x = b, which I want to solve for x. In another project I used a solver from the Eigen libary but now I want to calculate it in OpenFOAM. It is possible to solve this linear equation or do I need to use a fvMatrix type for A ?

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August 10, 2015, 05:44		#2
Rutger New Member Join Date: Aug 2015 Posts: 4 Rep Power: 11	For everyone with the same problem: The example in application/test/Matrix/Test-Matrix.C helped a lot. Now I'm copying the values from the vol*Field to the corresponding datatypes and solve the system.

August 10, 2015, 10:13		#3
Tushar@cfd Senior Member T. Chourushi Join Date: Jul 2009 Posts: 321 Blog Entries: 1 Rep Power: 18	Dear Rutger, Have a look to the eigen value solver given in Tensor.C file. I think this will help you. - Best Luck!

August 13, 2015, 08:26		#4
Rutger New Member Join Date: Aug 2015 Posts: 4 Rep Power: 11	Thanks, I will have a look at it.