On Thu, Apr 5, 2012 at 08:22, Abdul Hanan Sheikh <hanangul12 at yahoo.co.uk>wrote:
> For the system Au = f, I want to apply a multilevel preconditioner with a > KSP (say FGMRES) . The preconditioner > reads as > > Prec = C + M^-1 (I - A*C) , where > > > - C reads coarse grid correction operator i.e. C = P*A_2h\R [ R > restriction, A_2h coarse operator, P interpolation] > - M is say some sparse matrix (resembling to A) > > What makes it multilevel is I have to approximate coarse operator "A_2h" > with few KSP iterations preconditioned by the above defined > preconditioner "Prec" , but off course at the level 2h and hence at every > coarse level until coarsest. > Hmm, if you use a constant number of iterations in C at each level, the number of coarsest grid iterations will grow exponentially in the number of levels. Is that really what you want? > I only know, it can be implemented with PCMG. I am little afraid of DMMG. > Don't use DMMG, it is being removed. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120405/6be581ae/attachment-0001.htm>
