On Sun, Jul 31, 2016 at 4:56 PM, Stefano Zampini <[email protected]> wrote:
> It’s the first time I’m trying to setup field split so maybe I’m missing > something > > I have a MatNest with NULL (1,1) block. I setup the field split using the > row ISs from the MatNest (a note aside: why they cannot be inferred by > FieldSplit if pc->pmat is of type MatNEST?) > Options used are -pc_fieldsplit_type additive and > -pc_fieldsplit_detect_saddle_point > You don't need ISes is you use detect_saddle_point, so use one or the other. > I then get this error, because MatGetSubMatrix_Nest returns a NULL pointer. > What is the solution? having MatGetSubMatrix_Nest return a zero-valued > matrix of correct size? any command line option I’m not using? Or instead > having Fieldsplit handle the case? > I think have Nest return a real matrix is the right solution, since this is what will happen with other types. Matt > [0]PETSC ERROR: --------------------- Error Message > -------------------------------------------------------------- > [0]PETSC ERROR: Null argument, when expecting valid pointer > [0]PETSC ERROR: Null Object: Parameter # 1 > [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html > for trouble shooting. > [0]PETSC ERROR: Petsc Development GIT revision: v3.7.2-744-gb54d608 GIT > Date: 2016-06-28 18:20:20 +0300 > [0]PETSC ERROR: Unknown Name on a debug named kl-13916.local by szampini > Sun Jul 31 14:47:53 2016 > [0]PETSC ERROR: Configure options --download-chaco --download-ctetgen > --download-exodusii --download-hdf5 --download-hypre --download-metis > --download-mpich --download-mumps --download-netcdf --download-p4est > --download-parmetis --download-ptscotch --download-scalapack > --download-suitesparse --download-triangle --with-valgrind-dir=/usr/local/ > CC=/usr/local/bin/gcc-5 CXX=/usr/local/bin/g++-5 > FC=/usr/local/bin/gfortran-5 PETSC_ARCH=debug > [0]PETSC ERROR: #1 MatSetOptionsPrefix() line 654 in > /Users/szampini/software/petsc/src/mat/interface/matrix.c > [0]PETSC ERROR: #2 PCSetUp_FieldSplit() line 558 in > /Users/szampini/software/petsc/src/ksp/pc/impls/fieldsplit/fieldsplit.c > [0]PETSC ERROR: #3 PCSetUp() line 968 in > /Users/szampini/software/petsc/src/ksp/pc/interface/precon.c > > -- 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
