GAMG Solver

July 22, 2007, 04:23

Hello all,
does anyone of you know more about the GAMG Solver which is used in openFOAM 1.4, or know a paper where this multigrid method is proposed? Unfortunately I didn't find anything about it.

In of1.3 just an AMG was offered for symmetric matrices, does the GAMG mean now that it is a mixture and the geometric mg is used for asymmetric matrices, where AMG is still used for symmetric matrices?

Cheers
Florian

July 25, 2007, 05:35

Does anyone know if I'm right with my assumption, or is different?

Cheers
Florian

eugene · July 25, 2007, 12:18

GAMG can be used for both symmetric and asymetric matrices, and is basically an upgrade for the old AMG. However, it is not very cost effective to use GAMG for asymmetric matrices at present.

September 20, 2007, 04:53

Hi Eugene,

So what would you advise for a preconditioner instead of PCG and GAMG
for asymetric matrices?

Rgds

Pvc

eugene · September 20, 2007, 05:53

For asymmetric matrices I generally use the smoothSolver with GaussSeidel smoother.

immortality · January 26, 2013, 16:01

any information about GAMG solver and its coefficients?

July 22, 2007, 04:23	Hello all, does anyone of you	#1
tutlhino Guest Posts: n/a	Hello all, does anyone of you know more about the GAMG Solver which is used in openFOAM 1.4, or know a paper where this multigrid method is proposed? Unfortunately I didn't find anything about it. In of1.3 just an AMG was offered for symmetric matrices, does the GAMG mean now that it is a mixture and the geometric mg is used for asymmetric matrices, where AMG is still used for symmetric matrices? Cheers Florian

July 25, 2007, 05:35	Does anyone know if I'm right	#2
tutlhino Guest Posts: n/a	Does anyone know if I'm right with my assumption, or is different? Cheers Florian

July 25, 2007, 12:18	GAMG can be used for both symm	#3
eugene Senior Member Eugene de Villiers Join Date: Mar 2009 Posts: 725 Rep Power: 21	GAMG can be used for both symmetric and asymetric matrices, and is basically an upgrade for the old AMG. However, it is not very cost effective to use GAMG for asymmetric matrices at present.

September 20, 2007, 04:53	Hi Eugene, So what would y	#4
pvc Guest Posts: n/a	Hi Eugene, So what would you advise for a preconditioner instead of PCG and GAMG for asymetric matrices? Rgds Pvc

September 20, 2007, 05:53	For asymmetric matrices I gene	#5
eugene Senior Member Eugene de Villiers Join Date: Mar 2009 Posts: 725 Rep Power: 21	For asymmetric matrices I generally use the smoothSolver with GaussSeidel smoother.

January 26, 2013, 16:01		#6
immortality Senior Member Ehsan Join Date: Oct 2012 Location: Iran Posts: 2,208 Rep Power: 26	any information about GAMG solver and its coefficients?

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