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
