On Wed, Nov 1, 2023 at 9:32 PM Matthew Knepley <knep...@gmail.com> wrote:
> On Wed, Nov 1, 2023 at 3:59 PM Tang, Qi via petsc-users < > petsc-users@mcs.anl.gov> wrote: > >> Hi, >> >> I have a block matrix with type of MATNEST, but can I call >> -pc_fieldsplit_detect_saddle_point to change its IS? I assume it is not >> possible. >> > > The detection part will work since MatGetDiagonal() is supported, but we > do not have code in there > to take arbitrary blocks from MATNEST since the whole point is to get > no-copy access. Detection is > not needed in the case that the blocks line up. > > >> Also, I notice there is a small but important typo in the new fieldsplit >> doc: >> https://petsc.org/release/manualpages/PC/PCFIELDSPLIT/ >> The first matrix of the full factorization misses A10. I believe it >> should be >> [I -ksp(A00) A01] >> [ I ] >> > > Yes, that is right. > Fixed: https://gitlab.com/petsc/petsc/-/merge_requests/6993 THanks, Matt > Thanks, > > Matt > > >> Best, >> Qi >> > > > -- > 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 > > https://www.cse.buffalo.edu/~knepley/ > <http://www.cse.buffalo.edu/~knepley/> > -- 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 https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>