Hello, I’m trying something like: 1) create a Mat 2) setup a KSP and PCFIELDSPLIT 3) change the sparsity pattern of the Mat for one of the field 4) do a KSPSolve I cannot change this calling sequence, because I’d like to nest 3) and 4) inside a loop. However, I end up with this error during 4): [0]PETSC ERROR: Nonconforming object sizes [0]PETSC ERROR: Cannot reuse matrix. wrong no of nonzeros [0]PETSC ERROR: Petsc Development GIT revision: v3.9-13-g05d412bc58 GIT Date: 2018-04-09 08:39:52 -0500
[0]PETSC ERROR: #1 MatCreateSubMatrix_SeqAIJ() line 2330 in /Users/jolivet/Documents/repositories/petsc/src/mat/impls/aij/seq/aij.c [0]PETSC ERROR: #2 MatCreateSubMatrix_MPIAIJ_SameRowColDist() line 3184 in /Users/jolivet/Documents/repositories/petsc/src/mat/impls/aij/mpi/mpiaij.c [0]PETSC ERROR: #3 MatCreateSubMatrix_MPIAIJ() line 3310 in /Users/jolivet/Documents/repositories/petsc/src/mat/impls/aij/mpi/mpiaij.c [0]PETSC ERROR: #4 MatCreateSubMatrix() line 7813 in /Users/jolivet/Documents/repositories/petsc/src/mat/interface/matrix.c [0]PETSC ERROR: #5 PCSetUp_FieldSplit() line 564 in /Users/jolivet/Documents/repositories/petsc/src/ksp/pc/impls/fieldsplit/fieldsplit.c [0]PETSC ERROR: #6 PCSetUp() line 923 in /Users/jolivet/Documents/repositories/petsc/src/ksp/pc/interface/precon.c [0]PETSC ERROR: #7 PCApply() line 453 in /Users/jolivet/Documents/repositories/petsc/src/ksp/pc/interface/precon.c [0]PETSC ERROR: #8 KSP_PCApply() line 276 in /Users/jolivet/repo/petsc/include/petsc/private/kspimpl.h [0]PETSC ERROR: #9 KSPFGMRESCycle() line 166 in /Users/jolivet/Documents/repositories/petsc/src/ksp/ksp/impls/gmres/fgmres/fgmres.c [0]PETSC ERROR: #10 KSPSolve_FGMRES() line 291 in /Users/jolivet/Documents/repositories/petsc/src/ksp/ksp/impls/gmres/fgmres/fgmres.c [0]PETSC ERROR: #11 KSPSolve() line 669 in /Users/jolivet/Documents/repositories/petsc/src/ksp/ksp/interface/itfunc.c Is this the expected behaviour? Would you need a MWE? What I find funny is that if I turn -info on, then just before the error, I get: [0] PCSetUp(): Setting up PC with different nonzero pattern So why is it trying to reuse the matrix? I am missing a call to some function? Thanks in advance, Pierre