If this is what you want to do then just use the PCCOMPOSITE. Use PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE
Barry On May 11, 2012, at 6:26 AM, Hui Zhang wrote: > I want to implement the two-level Schwarz method. Let us denote P as the > one-level > Schwarz projection and P_0 as the coarse projection. If I want the hybrid > form of > preconditioned system as follows: > > (I-P_0) P (I-P_0) > > which is suitable: PCMG or PCComposite? It seems to me that PCComposite is > good. > But PCMG is not suitable because it can only implement the following form: > > (I-P) P_0 (I-P) > > Any opinions? Thanks! > >
