Explanation of "solve"-function

Linse · February 15, 2012, 05:16

Hello out there in the big OpenFOAM-world.

Is there anybody who can really explain to me the solve-function?
If I look at

Code:

->solve(psiCmpt, sourceCmpt, cmpt);

within finiteVolume/lnInclude/fvMatrixSolve.C at line 148 it seems to me there the real solver is pointed to, which uses the parameters psiCmpt, sourceCmpt and cmpt.
- But where is that solver really defined?
- Where can i find the actual definition of the function "solve()"?

And if there is somebody really knowing about that solve-function:
- Is there a way to call that solve() for a specific cell only?

I am kind of lost with the C++ stuff or at least inside the structure of OpenFOAM, so any help is welcome!

Taozi · February 1, 2015, 00:41

Hi Bernhard, did you find any information regarding the functionality of the solve() function? Thanks.

alberto · February 1, 2015, 23:30

The solve function you are looking at is a virtual function ( http://foam.sourceforge.net/docs/cpp/a02380.html ) which is redefined for each solver (diagonalSolver, GAMGSolver, ...).

If you want to solve a linear system directly in a cell or a limited number of cells, you probably want to follow a simpler way. You can, for example, use a scalarSquareMatrix and use LU decomposition on it (OF can do it).

February 15, 2012, 05:16	Explanation of "solve"-function	#1
Linse Senior Member Bernhard Linseisen Join Date: May 2010 Location: Heilbronn Posts: 183 Blog Entries: 1 Rep Power: 15	Hello out there in the big OpenFOAM-world. Is there anybody who can really explain to me the solve-function? If I look at Code: ->solve(psiCmpt, sourceCmpt, cmpt); within finiteVolume/lnInclude/fvMatrixSolve.C at line 148 it seems to me there the real solver is pointed to, which uses the parameters psiCmpt, sourceCmpt and cmpt. - But where is that solver really defined? - Where can i find the actual definition of the function "solve()"? And if there is somebody really knowing about that solve-function: - Is there a way to call that solve() for a specific cell only? I am kind of lost with the C++ stuff or at least inside the structure of OpenFOAM, so any help is welcome!

February 1, 2015, 23:30		#3
alberto Senior Member Alberto Passalacqua Join Date: Mar 2009 Location: Ames, Iowa, United States Posts: 1,912 Rep Power: 36	The solve function you are looking at is a virtual function ( http://foam.sourceforge.net/docs/cpp/a02380.html ) which is redefined for each solver (diagonalSolver, GAMGSolver, ...). If you want to solve a linear system directly in a cell or a limited number of cells, you probably want to follow a simpler way. You can, for example, use a scalarSquareMatrix and use LU decomposition on it (OF can do it). snak, sharonyue, Taozi and 2 others like this. __________________ Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using. Last edited by alberto; February 1, 2015 at 23:47. Reason: Corrected answer

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February 1, 2015, 00:41		#2
Taozi New Member Chenguang Zhang Join Date: Jul 2012 Location: Baton Rouge Louisiana Posts: 15 Rep Power: 13	Hi Bernhard, did you find any information regarding the functionality of the solve() function? Thanks.