Please send a complete code that you think should work that doesn't so we can understand the exact issue.
> On Jul 26, 2016, at 10:54 PM, Safin, Artur <aks084...@utdallas.edu> wrote: > > Barry, > >> Do you have a call to KSPSetFromOptions() before the call >> PCFieldSplitGetSubKSP()? I am guessing not which means that the PC does not >> yet know that it is of type fieldplit. > > Yes, I call KSPSetFromOptions() for the global matrix at the beginning of the > code. Should I also do it for the ksp I obtain from PCFieldSplitGetSubKSP()? > > The program has no problem doing fieldsplit for the global matrix; my issue > is that I cannot get it to recognize a fieldsplit within a fieldsplit. > > This is the whole code for the solver: > > -------------------------------------------------------------------------------------------------------------------------------- > KSP ksp; > KSPCreate(mpi_communicator, &ksp); > KSPSetType(ksp, KSPGMRES); > KSPSetOperators(ksp, A_petsc, A_petsc); > KSPSetFromOptions(ksp); > > PC pc; > KSPGetPC(ksp, &pc); > > // Define the fieldsplit for the global matrix > PCFieldSplitSetIS(pc, "P", P_IS); > PCFieldSplitSetIS(pc, "T", T_IS); > > // fieldsplit for submatrix P: > KSP *ksp_all, ksp_P; > PCFieldSplitGetSubKSP(pc, &i, &ksp_all); > > ksp_P = ksp_all[0]; > PC pc_P; > KSPGetPC(ksp_P, &pc_P); // This should be the preconditioner for fieldsplit P > PCFieldSplitSetIS(pc_P, "A", P_A_IS); > PCFieldSplitSetIS(pc_P, "B", P_B_IS); > > KSPSolve(ksp, b_petsc, u_petsc); > -------------------------------------------------------------------------------------------------------------------------------- > > Thanks, > > Artur >
