On Fri, Mar 13, 2009 at 4:39 PM, Ravi Kannan <rxk at cfdrc.com> wrote:
> Hi Matt > > Are you suggesting to use MatGetOrdering()? > That is one way. > Will it work for parallel matrix? > It depends on the particular ordering, but I think most do. Matt > Thanks. > > Ravi > > -----Original Message----- > *From:* petsc-users-bounces at mcs.anl.gov [mailto: > petsc-users-bounces at mcs.anl.gov]*On Behalf Of *Matthew Knepley > *Sent:* Friday, March 13, 2009 11:34 AM > *To:* PETSc users list > *Subject:* Re: matrix assembling time > > On Fri, Mar 13, 2009 at 12:48 PM, Ravi Kannan <rxk at cfdrc.com> wrote: > >> Hi, >> This is Ravi Kannan from CFD Research Corporation. One basic question >> on >> the ordering of linear solvers in PETSc: If my A matrix (in AX=B) is a >> sparse matrix and the bandwidth of A (i.e. the distance between non zero >> elements) is high, does PETSc reorder the matrix/matrix-equations so as to >> solve more efficiently. If yes, is there any specific command to do the >> above? > > > You can reorder the matrix using the MatOrdering class. > > Matt > > >> >> Thanks >> Ravi >> >> >> >> -----Original Message----- >> From: petsc-users-bounces at mcs.anl.gov >> [mailto:petsc-users-bounces at mcs.anl.gov]On Behalf Of Yixun Liu >> Sent: Friday, March 06, 2009 12:50 PM >> To: PETSC >> Subject: matrix assembling time >> >> >> Hi, >> Using PETSc the assembling time for a mesh with 6000 vertices is about >> 14 second parallelized on 4 processors, but another sequential program >> based on gmm lib is about 0.6 second. PETSc's solver is much faster than >> gmm, but I don't know why its assembling is so slow although I have >> preallocate an enough space for the matrix. >> >> MatMPIAIJSetPreallocation(sparseMeshMechanicalStiffnessMatrix, 1000, >> PETSC_NULL, 1000, PETSC_NULL); >> >> Yixun >> >> >> > > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20090313/5e5a1b8b/attachment.htm>
