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.
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
