Parameters for multigrid solver
Hello!
I'm working with OpenFOAM1.6ext since last October. My task is to study the numerical methods like the ode solvers and matrix solvers. I've already finished to learn the theory about all methods and now I have to test them. For the tests I'm solving a steady state flame with reactingFoam. Now I tried to solve the matrices with the xxAMG solvers and I'm wondering what all the parameters are saying. I got them with some debugging voodoo and I'm also wondering if there are any more parameters which are not necessary, but maybe useful. For the GAMG solver I already got the parameters from this thread. And of course I read the linked two papers. On that basis I tried to get the MPEAMG, RREAMG and FPEAMG solvers running. I managed them to get started, but I don't know what most parameters are doing. Can anybody explain the following parameters where a question or no comment is posted. And maybe give some rule of thumb for their values? The not indented parameters are from GAMG, the fist block of indented parameters is from MPEAMG and the second indented block is additional necessary for FPEAMG. Code:
U xxEAMG HaZe 
Quote:

I found some comments in older source code (blue) from OF1.5dev on the net, but there are still some questions left (green).
Any suggestions for the numeric values, especially in view of their dependencies? Code:
U xxEAMG 
Quote:
I am thinking that since various multigrids are implemented by various people there might be overlap of some parameters. About this: maxIter 500; // is this the max number of V/W/F cylces in one time step? This value look to be ridiculously high. Fluent's default value is 30 and perhaps straccm+ default is 50 or also 30. It does not take this many cycles to reach there. Today i finished implementing coupled multigrid for pressure based coupled solver. It normally takes around 10 cycles to drop error to 1E5 levels using V cycle. And this problem is supposed to be very difficult to converge. 
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