[msrinath80]

In OF 1.3, we used the following syntax in the fvSolution file:

p AMG 1e-06 0 25;

If I were to translate the same into OF 1.4, I would expect the following syntax:

p GAMG
{
tolerance 1e-06;
relTol 0;
nCellsInCoarsestLevel 25;

};

My question is whether we need to specify nPreSweeps, nPostSweeps and nFinestSweeps? Also, can someone explain the use of mergeLevels?

Also what smoothers are available?

Many thanks!

[eugene]

mergeLevels is the number of merge operations to do between grid levels. mergeLevel 1 is equivalent to what is hard coded in AMG and is what I normally use.

agglomerator faceAreaPair; seems to work best

smoother options are: GaussSeidel, DIC and DICGausSeidel. GausSeidel seems to work best, but DICGaussSeidel might be better for more difficult problems. It is more expensive though.

nPreSweeps, nPostSweeps, nFinestSweeps: I use 0,2,2 and this should work for most problems. Feel free to experiment though.

[msrinath80]

Many thanks for that clear explanation Eugene!