On Wed, Dec 4, 2019 at 8:20 AM Cotter, Colin J <[email protected]> wrote:
> Dear PETSc users, > I'm curious: how does PETSc compute the Schur complement matrix under > the option pc_fieldsplit_schur_precondition full? Does it use sparse linear > algebra? > The action of the Schur complement is always MatMult() KSPSolve() MatMult(). The precondition matrix can be formed several different ways: https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCFieldSplitSetSchurPre.html Thanks, Matt > all the best > --Colin > > -- 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/>
