On May 11, 2012, at 2:55 PM, Barry Smith wrote: > > If this is what you want to do then just use the PCCOMPOSITE. Use > PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE > > Barry
Aha, I see. Thank you, Barry! Just one more question on PCCompositeAddPC: is firstly added PC also firstly applied, i.e. the order of applying PC's is the same as the order of PCCompositeAddPC ? > > 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! >> >> > >
