Hi, Thank you Mark.
Let me clarify my questions; 1-)How to implement or activate a Reorthogonalization procedure for KSPCG.. As you know, search directions can be found more rapidly (with less numer of iterations) by using previous successive directions 2-) How to implement or activate a projection space over CG. A sample projection can be; P = I - G*((G'*G)\G'). I need to insert project,scale,precondition,re-scae,re-project steps during each KSPCG iteration. How can I utilize this? Thanks again and merry christmas to all On Sun, Dec 28, 2014 at 4:28 PM, Mark Adams <[email protected]> wrote: > > > On Sat, Dec 27, 2014 at 5:00 AM, Alp Kalpalp <[email protected]> wrote: > >> Hi, >> >> I implemented a newmark time stepping algorithm without using TS >> structure. I am following ex59 about PCBDDC. >> >> > use TS > > >> ComputeMatrix >> ComputeKSPBDDC >> >> for // a time loop >> { >> Compute RHS >> KSPSolve >> GatherResults >> MoveToNextTS >> } >> >> >> However, when I watch the iteration counts of KSPSolve they do not >> decrease signicantly..Decrease was around 5%. >> >> So I have some problems; >> >> 1-) I guess currently, factorization is not taking place for each time >> step in my code. Ok this is expected. But I wonder whether Kspsolve stores >> the Krylov subspace vectors and reuse them for the next time step. >> >> > No. Certainly not by default. > > >> 2-) PCBDDC uses KSPCG and AFAIK petsc doesnot have preconditioned >> conjugate projected gradient (PCPG). Is it possible to simulate PCPG >> iteration in some way? >> >> > KSP has a PC object and all methods use it AFAIK. > > >> Thanks, >> >> >> >
