[petsc-dev] Parallel Gauss - Seidel

[Mark F. Adams]

I would like a parallel G-S to PETSc.  I have to design questions:

1) I need a G-S kernel that takes an IS of indices to process and a flag to process them in forward or reverse order.  How should I proceed to do this.  Should I just clone sor?

2) I don't want to use Richardson iterations for G-S.  Should I make a G-S KPS method?  I don't want to take a residual in the iterator (KSP) and if symmetric G-S is requested then it should drive this I think.  SOR does two sweeps in each application; I'm not wild about that because a good way to run G-S in a V(1,1) cycle is to do a forward sweep in pre smoothing and a backward sweep in post smoothing.  Any thoughts? (that's a rhetorical question Jed).

Mark