> On 18 Sep 2019, at 3:48 PM, Matthew Knepley <[email protected]> wrote: > > On Wed, Sep 18, 2019 at 2:49 AM Pierre Jolivet via petsc-dev > <[email protected] <mailto:[email protected]>> wrote: > Hello, > I’m solving the following dummy system > http://jolivet.perso.enseeiht.fr/composite_ksp.tar.gz > <http://jolivet.perso.enseeiht.fr/composite_ksp.tar.gz> > [A, B];[C, D], with a PCFIELDSPLIT. For the PC of D, I’m using a PCCOMPOSITE > with two sub PCs. One of which is a PCKSP. > Could you please help me figure out what is wrong in the following piece of > code, that may be launched with the following arguments: > $ mpirun -n 1 ./a.out -ksp_type preonly -pc_type fieldsplit > -fieldsplit_1_pc_type composite -fieldsplit_1_sub_1_pc_type ksp > -fieldsplit_1_sub_1_ksp_ksp_type gmres -fieldsplit_1_sub_1_ksp_pc_type gamg > -fieldsplit_1_sub_1_ksp_ksp_converged_reason > -fieldsplit_1_sub_1_ksp_pc_gamg_sym_graph 1 > -fieldsplit_1_sub_1_ksp_pc_gamg_square_graph 10 > -fieldsplit_1_sub_1_ksp_ksp_rtol 1e-8 > > It solves the dummy system twice, with a varying block D. > > Its not the PC, its the matrix. Everything in the PC gets resetup just like > you want. > > I did MatEqual(S2_1, S2_001, &equal) and equal was false.
They are not supposed to be equal, so that’s a good thing. Or are you doing the comparison _after_ the MatCopy? I’m not sure of what is your point, sorry. Thanks, Pierre > Thanks, > > Matt > > It should give you: > Linear fieldsplit_1_sub_1_ksp_ solve converged due to CONVERGED_RTOL > iterations 8 > solve #0: 16098.3 > Linear fieldsplit_1_sub_1_ksp_ solve did not converge due to > DIVERGED_PC_FAILED iterations 0 > PC_FAILED due to SUBPC_ERROR > solve #1: inf > > If I switch line 70 to #if 0, I get the expected output: > Linear fieldsplit_1_sub_1_ksp_ solve converged due to CONVERGED_RTOL > iterations 8 > solve #0: 16098.3 > Linear fieldsplit_1_sub_1_ksp_ solve converged due to CONVERGED_RTOL > iterations 8 > solve #1: 325.448 > > I’m realizing that this has probably nothing to do with the outer > PCFIELDSPLIT, but this comes from a rather large FSI solver, so reproducing > this behavior in “only” 97 SLOC is good enough for your I hope. > > Thanks in advance, > Pierre > > > -- > 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/>
