You are right. What was Victor thinking? Seems a pretty strange algorithm in that case. I have updated the manual page yet again to reflect this.
Barry I am not sure we really want to have this behavior, seems too likely to perform badly. On Fri, 12 Oct 2007, Lisandro Dalcin wrote: > But for cgne, looking at the code, ApplyTranspose seems to be optional... > > On 10/11/07, Barry Smith <bsmith at mcs.anl.gov> wrote: > > > > [bsmith:~] bsmith% cd Src/petsc-dev/src/ksp/ksp/impls > > [bsmith:ksp/ksp/impls] bsmith% grep ApplyTranspose */*.c > > bicg/bicg.c: ierr = KSP_PCApplyTranspose(ksp,Rl,Zl);CHKERRQ(ierr); > > bicg/bicg.c: ierr = KSP_PCApplyTranspose(ksp,Rl,Zl);CHKERRQ(ierr); > > bicg/bicg.c: ierr = KSP_PCApplyTranspose(ksp,Rl,Zl);CHKERRQ(ierr); > > > > [bsmith:ksp/ksp/impls] bsmith% grep ApplyTranspose */*/*.c > > cg/cgne/cgne.c: ierr = > > PCApplyTransposeExists(ksp->pc,&transpose_pc);CHKERRQ(ierr); > > cg/cgne/cgne.c: ierr = KSP_PCApplyTranspose(ksp,T,Z);CHKERRQ(ierr); > > cg/cgne/cgne.c: ierr = KSP_PCApplyTranspose(ksp,T,Z);CHKERRQ(ierr); > > > > These are the two methods that require the transpose operation. > > > > I have documented both of their manual pages to indicate this. > > > > Barry > > > > > > On Thu, 11 Oct 2007, Keita Teranishi wrote: > > > > > Hi Barry, > > > > > > Could you suggest any other KSP solvers that have the same type of > > > problems? > > > > > > Thanks, > > > ================================ > > > Keita Teranishi > > > Math Software Group > > > Cray Inc. > > > keita at cray.com > > > ================================ > > > > > > -----Original Message----- > > > From: owner-petsc-users at mcs.anl.gov [mailto:owner-petsc-users at > > > mcs.anl.gov] On Behalf Of Barry Smith > > > Sent: Thursday, October 11, 2007 4:50 PM > > > To: petsc-users at mcs.anl.gov > > > Subject: Re: Preconditioner for bicg > > > > > > > > > For some preconditioners it is simply not easily possible to apply the > > > transpose of the preconditioner. Even multigrid requires some work to do > > > this. > > > > > > Barry > > > > > > > > > On Thu, 11 Oct 2007, Keita Teranishi wrote: > > > > > > > Hi, > > > > > > > > > > > > > > > > I'd like to make sure preconditioners supported for bicg. I found bicg > > > > only accepts preconditioners that is interfaced through > > > > PCApplyTranspose. > > > > > > > > For this reason, I see several preconditioners fails with bicg. > > > > > > > > > > > > > > > > Thanks, > > > > > > > > ================================ > > > > Keita Teranishi > > > > Math Software Group > > > > Cray Inc. > > > > keita at cray.com > > > > ================================ > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
