> On May 30, 2024, at 3:15 PM, Colton Bryant > <[email protected]> wrote: > > Hi Barry, > > Do you know of an example that demonstrates this approach? I have tried > implementing this using DMStagCreateISFromStencils and then calling > PCFieldSplitSetIS with fields named "velocity" and "pressure" respectively, > but when I look at -ksp_view the fields are being set to "fieldsplit_face" > and "fieldsplit_element" and as problems are not converging I expect the > constant null space is not being attached.
First confirm that each IS has the entries you expect Then for the pressure IS are you using PetscObjectCompose((PetscObject*)is,"nullspace", (PetscObject *)sp); where sp is the null space of the pressure variables which I think you can create using MatNullSpaceCreate(comm,PETSC_TRUE,0,NULL,&sp); PCFIELDSPLIT is suppose to snag this null space that you provided and use it on the Shur system. If you run with -ksp_view it should list what matrices have an attached null space. > > Thanks, > Colton > > On Thu, May 23, 2024 at 12:55 PM Barry Smith <[email protected] > <mailto:[email protected]>> wrote: >> >> Unfortunately it cannot automatically because >> -pc_fieldsplit_detect_saddle_point just grabs part of the matrix (having no >> concept of "what part" so doesn't know to grab the null space information. >> >> It would be possible for PCFIELDSPLIT to access the null space of the >> larger matrix directly as vectors and check if they are all zero in the 00 >> block, then it would know that the null space only applied to the second >> block and could use it for the Schur complement. >> >> Matt, Jed, Stefano, Pierre does this make sense? >> >> Colton, >> >> Meanwhile the quickest thing you can do is to generate the IS the >> defines the first and second block (instead of using >> -pc_fieldsplit_detect_saddle_point) and use PetscObjectCompose to attach the >> constant null space to the second block with the name "nullspace". >> PCFIELDSPLIT will then use this null space for the Schur complement solve. >> >> Barry >> >> >>> On May 23, 2024, at 2:43 PM, Colton Bryant >>> <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> Yes, the original operator definitely has a constant null space >>> corresponding to the constant pressure mode. I am currently handling this >>> by using the MatSetNullSpace function when the matrix is being created. >>> Does this information get passed to the submatrices of the fieldsplit? >>> >>> -Colton >>> >>> On Thu, May 23, 2024 at 12:36 PM Barry Smith <[email protected] >>> <mailto:[email protected]>> wrote: >>>> >>>> Ok, >>>> >>>> So what is happening is that GMRES with a restart of 30 is running on >>>> the Schur complement system with no preconditioning and LU (as a direct >>>> solver) is being used in the application of S (the Schur complement). The >>>> convergence of GMRES is stagnating after getting about 8 digits of >>>> accuracy in the residual. Then at the second GMRES >>>> restart it is comparing the explicitly computing residual b - Ax with that >>>> computed inside the GMRES algorithm (via a recursive formula) and finding >>>> a large difference so generating an error. Since you are using a direct >>>> solver on the A_{00} block and it is well-conditioned this problem is not >>>> expected. >>>> >>>> Is it possible that the S operator has a null space (perhaps of the >>>> constant vector)? Or, relatedly, does your original full matrix have a >>>> null space? >>>> >>>> We have a way to associated null spaces of the submatrices in >>>> PCFIELDSPLIT by attaching them to the IS that define the fields, but >>>> unfortunately not trivially when using -pc_fieldsplit_detect_saddle_point. >>>> And sadly the current support seems completely undocumented. >>>> >>>> Barry >>>> >>>> >>>> >>>>> On May 23, 2024, at 2:16 PM, Colton Bryant >>>>> <[email protected] >>>>> <mailto:[email protected]>> wrote: >>>>> >>>>> Hi Barry, >>>>> >>>>> I saw that was reporting as an unused option and the error message I sent >>>>> was run with -fieldsplit_0_ksp_type preonly. >>>>> >>>>> -Colton >>>>> >>>>> On Thu, May 23, 2024 at 12:13 PM Barry Smith <[email protected] >>>>> <mailto:[email protected]>> wrote: >>>>>> >>>>>> >>>>>> Sorry I gave the wrong option. Use -fieldsplit_0_ksp_type preonly >>>>>> >>>>>> Barry >>>>>> >>>>>>> On May 23, 2024, at 12:51 PM, Colton Bryant >>>>>>> <[email protected] >>>>>>> <mailto:[email protected]>> wrote: >>>>>>> >>>>>>> That produces the error: >>>>>>> >>>>>>> [0]PETSC ERROR: Residual norm computed by GMRES recursion formula >>>>>>> 2.68054e-07 is far from the computed residual norm 6.86309e-06 at >>>>>>> restart, residual norm at start of cycle 2.68804e-07 >>>>>>> >>>>>>> The rest of the error is identical. >>>>>>> >>>>>>> On Thu, May 23, 2024 at 10:46 AM Barry Smith <[email protected] >>>>>>> <mailto:[email protected]>> wrote: >>>>>>>> >>>>>>>> Use -pc_fieldsplit_0_ksp_type preonly >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> On May 23, 2024, at 12:43 PM, Colton Bryant >>>>>>>>> <[email protected] >>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>> >>>>>>>>> That produces the following error: >>>>>>>>> >>>>>>>>> [0]PETSC ERROR: Residual norm computed by GMRES recursion formula >>>>>>>>> 2.79175e-07 is far from the computed residual norm 0.000113154 at >>>>>>>>> restart, residual norm at start of cycle 2.83065e-07 >>>>>>>>> [0]PETSC ERROR: See >>>>>>>>> https://urldefense.us/v3/__https://petsc.org/release/faq/__;!!G_uCfscf7eWS!c81JFRKh9FMvhtMT3DHjss1cBEK_pT65OMx-6jt79o25gDpLWKcnFNqDpxJPwfQ4KkOdlgoFUso9HgpAHxZxBB4$ >>>>>>>>> for trouble shooting. >>>>>>>>> [0]PETSC ERROR: Petsc Release Version 3.21.0, unknown >>>>>>>>> [0]PETSC ERROR: ./mainOversetLS_exe on a arch-linux-c-opt named glass >>>>>>>>> by colton Thu May 23 10:41:09 2024 >>>>>>>>> [0]PETSC ERROR: Configure options --download-mpich --with-cc=gcc >>>>>>>>> --with-cxx=g++ --with-debugging=no --with-fc=gfortran COPTFLAGS=-O3 >>>>>>>>> CXXOPTFLAGS=-O3 FOPTFLAGS=-O3 PETSC_ARCH=arch-linux-c-opt >>>>>>>>> --download-sowing >>>>>>>>> [0]PETSC ERROR: #1 KSPGMRESCycle() at >>>>>>>>> /home/colton/petsc/src/ksp/ksp/impls/gmres/gmres.c:115 >>>>>>>>> [0]PETSC ERROR: #2 KSPSolve_GMRES() at >>>>>>>>> /home/colton/petsc/src/ksp/ksp/impls/gmres/gmres.c:227 >>>>>>>>> [0]PETSC ERROR: #3 KSPSolve_Private() at >>>>>>>>> /home/colton/petsc/src/ksp/ksp/interface/itfunc.c:905 >>>>>>>>> [0]PETSC ERROR: #4 KSPSolve() at >>>>>>>>> /home/colton/petsc/src/ksp/ksp/interface/itfunc.c:1078 >>>>>>>>> [0]PETSC ERROR: #5 PCApply_FieldSplit_Schur() at >>>>>>>>> /home/colton/petsc/src/ksp/pc/impls/fieldsplit/fieldsplit.c:1203 >>>>>>>>> [0]PETSC ERROR: #6 PCApply() at >>>>>>>>> /home/colton/petsc/src/ksp/pc/interface/precon.c:497 >>>>>>>>> [0]PETSC ERROR: #7 KSP_PCApply() at >>>>>>>>> /home/colton/petsc/include/petsc/private/kspimpl.h:409 >>>>>>>>> [0]PETSC ERROR: #8 KSPFGMRESCycle() at >>>>>>>>> /home/colton/petsc/src/ksp/ksp/impls/gmres/fgmres/fgmres.c:123 >>>>>>>>> [0]PETSC ERROR: #9 KSPSolve_FGMRES() at >>>>>>>>> /home/colton/petsc/src/ksp/ksp/impls/gmres/fgmres/fgmres.c:235 >>>>>>>>> [0]PETSC ERROR: #10 KSPSolve_Private() at >>>>>>>>> /home/colton/petsc/src/ksp/ksp/interface/itfunc.c:905 >>>>>>>>> [0]PETSC ERROR: #11 KSPSolve() at >>>>>>>>> /home/colton/petsc/src/ksp/ksp/interface/itfunc.c:1078 >>>>>>>>> [0]PETSC ERROR: #12 solveStokes() at cartesianStokesGrid.cpp:1403 >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On Thu, May 23, 2024 at 10:33 AM Barry Smith <[email protected] >>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>>> >>>>>>>>>> Run the failing case with also -ksp_error_if_not_converged so we >>>>>>>>>> see exactly where the problem is first detected. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>>> On May 23, 2024, at 11:51 AM, Colton Bryant >>>>>>>>>>> <[email protected] >>>>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>>>> >>>>>>>>>>> Hi Barry, >>>>>>>>>>> >>>>>>>>>>> Thanks for letting me know about the need to use fgmres in this >>>>>>>>>>> case. I ran a smaller problem (1230 in the first block) and saw >>>>>>>>>>> similar behavior in the true residual. >>>>>>>>>>> >>>>>>>>>>> I also ran the same problem with the options -fieldsplit_0_pc_type >>>>>>>>>>> svd -fieldsplit_0_pc_svd_monitor and get the following output: >>>>>>>>>>> SVD: condition number 1.933639985881e+03, 0 of 1230 singular >>>>>>>>>>> values are (nearly) zero >>>>>>>>>>> SVD: smallest singular values: 4.132036392141e-03 >>>>>>>>>>> 4.166444542385e-03 4.669534028645e-03 4.845532162256e-03 >>>>>>>>>>> 5.047038625390e-03 >>>>>>>>>>> SVD: largest singular values : 7.947990616611e+00 >>>>>>>>>>> 7.961437414477e+00 7.961851612473e+00 7.971335373142e+00 >>>>>>>>>>> 7.989870790960e+00 >>>>>>>>>>> >>>>>>>>>>> I would be surprised if the A_{00} block is ill conditioned as it's >>>>>>>>>>> just a standard discretization of the laplacian with some rows >>>>>>>>>>> replaced with ones on the diagonal due to interpolations from the >>>>>>>>>>> overset mesh. I'm wondering if I'm somehow violating a solvability >>>>>>>>>>> condition of the problem? >>>>>>>>>>> >>>>>>>>>>> Thanks for the help! >>>>>>>>>>> >>>>>>>>>>> -Colton >>>>>>>>>>> >>>>>>>>>>> On Wed, May 22, 2024 at 6:09 PM Barry Smith <[email protected] >>>>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>>>>> >>>>>>>>>>>> Thanks for the info. I see you are using GMRES inside the Schur >>>>>>>>>>>> complement solver, this is ok but when you do you need to use >>>>>>>>>>>> fgmres as the outer solver. But this is unlikely to be the cause >>>>>>>>>>>> of the exact problem you are seeing. >>>>>>>>>>>> >>>>>>>>>>>> I'm not sure why the Schur complement KSP is suddenly seeing a >>>>>>>>>>>> large increase in the true residual norm. Is it possible the >>>>>>>>>>>> A_{00} block is ill-conditioned? >>>>>>>>>>>> >>>>>>>>>>>> Can you run with a smaller problem? Say 2,000 or so in the >>>>>>>>>>>> first block? Is there still a problem? >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>>> On May 22, 2024, at 6:00 PM, Colton Bryant >>>>>>>>>>>>> <[email protected] >>>>>>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> Hi Barry, >>>>>>>>>>>>> >>>>>>>>>>>>> I have not used any other solver parameters in the code and the >>>>>>>>>>>>> full set of solver related command line options are those I >>>>>>>>>>>>> mentioned in the previous email. >>>>>>>>>>>>> >>>>>>>>>>>>> Below is the output from -ksp_view: >>>>>>>>>>>>> >>>>>>>>>>>>> KSP Object: (back_) 1 MPI process >>>>>>>>>>>>> type: gmres >>>>>>>>>>>>> restart=30, using Classical (unmodified) Gram-Schmidt >>>>>>>>>>>>> Orthogonalization with no iterative refinement >>>>>>>>>>>>> happy breakdown tolerance 1e-30 >>>>>>>>>>>>> maximum iterations=10000, initial guess is zero >>>>>>>>>>>>> tolerances: relative=1e-08, absolute=1e-50, divergence=10000. >>>>>>>>>>>>> left preconditioning >>>>>>>>>>>>> using PRECONDITIONED norm type for convergence test >>>>>>>>>>>>> PC Object: (back_) 1 MPI process >>>>>>>>>>>>> type: fieldsplit >>>>>>>>>>>>> FieldSplit with Schur preconditioner, blocksize = 1, >>>>>>>>>>>>> factorization FULL >>>>>>>>>>>>> Preconditioner for the Schur complement formed from S itself >>>>>>>>>>>>> Split info: >>>>>>>>>>>>> Split number 0 Defined by IS >>>>>>>>>>>>> Split number 1 Defined by IS >>>>>>>>>>>>> KSP solver for A00 block >>>>>>>>>>>>> KSP Object: (back_fieldsplit_0_) 1 MPI process >>>>>>>>>>>>> type: gmres >>>>>>>>>>>>> restart=30, using Classical (unmodified) Gram-Schmidt >>>>>>>>>>>>> Orthogonalization with no iterative refinement >>>>>>>>>>>>> happy breakdown tolerance 1e-30 >>>>>>>>>>>>> maximum iterations=10000, initial guess is zero >>>>>>>>>>>>> tolerances: relative=1e-05, absolute=1e-50, >>>>>>>>>>>>> divergence=10000. >>>>>>>>>>>>> left preconditioning >>>>>>>>>>>>> using PRECONDITIONED norm type for convergence test >>>>>>>>>>>>> PC Object: (back_fieldsplit_0_) 1 MPI process >>>>>>>>>>>>> type: lu >>>>>>>>>>>>> out-of-place factorization >>>>>>>>>>>>> tolerance for zero pivot 2.22045e-14 >>>>>>>>>>>>> matrix ordering: nd >>>>>>>>>>>>> factor fill ratio given 5., needed 8.83482 >>>>>>>>>>>>> Factored matrix follows: >>>>>>>>>>>>> Mat Object: (back_fieldsplit_0_) 1 MPI process >>>>>>>>>>>>> type: seqaij >>>>>>>>>>>>> rows=30150, cols=30150 >>>>>>>>>>>>> package used to perform factorization: petsc >>>>>>>>>>>>> total: nonzeros=2649120, allocated >>>>>>>>>>>>> nonzeros=2649120 >>>>>>>>>>>>> using I-node routines: found 15019 nodes, limit >>>>>>>>>>>>> used is 5 >>>>>>>>>>>>> linear system matrix = precond matrix: >>>>>>>>>>>>> Mat Object: (back_fieldsplit_0_) 1 MPI process >>>>>>>>>>>>> type: seqaij >>>>>>>>>>>>> rows=30150, cols=30150 >>>>>>>>>>>>> total: nonzeros=299850, allocated nonzeros=299850 >>>>>>>>>>>>> total number of mallocs used during MatSetValues calls=0 >>>>>>>>>>>>> using I-node routines: found 15150 nodes, limit used >>>>>>>>>>>>> is 5 >>>>>>>>>>>>> KSP solver for S = A11 - A10 inv(A00) A01 >>>>>>>>>>>>> KSP Object: (back_fieldsplit_1_) 1 MPI process >>>>>>>>>>>>> type: gmres >>>>>>>>>>>>> restart=30, using Classical (unmodified) Gram-Schmidt >>>>>>>>>>>>> Orthogonalization with no iterative refinement >>>>>>>>>>>>> happy breakdown tolerance 1e-30 >>>>>>>>>>>>> maximum iterations=10000, initial guess is zero >>>>>>>>>>>>> tolerances: relative=1e-08, absolute=1e-50, >>>>>>>>>>>>> divergence=10000. >>>>>>>>>>>>> left preconditioning >>>>>>>>>>>>> using PRECONDITIONED norm type for convergence test >>>>>>>>>>>>> PC Object: (back_fieldsplit_1_) 1 MPI process >>>>>>>>>>>>> type: none >>>>>>>>>>>>> linear system matrix = precond matrix: >>>>>>>>>>>>> Mat Object: (back_fieldsplit_1_) 1 MPI process >>>>>>>>>>>>> type: schurcomplement >>>>>>>>>>>>> rows=15000, cols=15000 >>>>>>>>>>>>> Schur complement A11 - A10 inv(A00) A01 >>>>>>>>>>>>> A11 >>>>>>>>>>>>> Mat Object: (back_fieldsplit_1_) 1 MPI process >>>>>>>>>>>>> type: seqaij >>>>>>>>>>>>> rows=15000, cols=15000 >>>>>>>>>>>>> total: nonzeros=74700, allocated nonzeros=74700 >>>>>>>>>>>>> total number of mallocs used during MatSetValues >>>>>>>>>>>>> calls=0 >>>>>>>>>>>>> not using I-node routines >>>>>>>>>>>>> A10 >>>>>>>>>>>>> Mat Object: 1 MPI process >>>>>>>>>>>>> type: seqaij >>>>>>>>>>>>> rows=15000, cols=30150 >>>>>>>>>>>>> total: nonzeros=149550, allocated nonzeros=149550 >>>>>>>>>>>>> total number of mallocs used during MatSetValues >>>>>>>>>>>>> calls=0 >>>>>>>>>>>>> not using I-node routines >>>>>>>>>>>>> KSP solver for A00 block viewable with the additional >>>>>>>>>>>>> option -back_fieldsplit_0_ksp_view >>>>>>>>>>>>> A01 >>>>>>>>>>>>> Mat Object: 1 MPI process >>>>>>>>>>>>> type: seqaij >>>>>>>>>>>>> rows=30150, cols=15000 >>>>>>>>>>>>> total: nonzeros=149550, allocated nonzeros=149550 >>>>>>>>>>>>> total number of mallocs used during MatSetValues >>>>>>>>>>>>> calls=0 >>>>>>>>>>>>> using I-node routines: found 15150 nodes, limit >>>>>>>>>>>>> used is 5 >>>>>>>>>>>>> linear system matrix = precond matrix: >>>>>>>>>>>>> Mat Object: (back_) 1 MPI process >>>>>>>>>>>>> type: seqaij >>>>>>>>>>>>> rows=45150, cols=45150 >>>>>>>>>>>>> total: nonzeros=673650, allocated nonzeros=673650 >>>>>>>>>>>>> total number of mallocs used during MatSetValues calls=0 >>>>>>>>>>>>> has attached null space >>>>>>>>>>>>> using I-node routines: found 15150 nodes, limit used is 5 >>>>>>>>>>>>> >>>>>>>>>>>>> Thanks again! >>>>>>>>>>>>> >>>>>>>>>>>>> -Colton >>>>>>>>>>>>> >>>>>>>>>>>>> On Wed, May 22, 2024 at 3:39 PM Barry Smith <[email protected] >>>>>>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>> Are you using any other command line options or did you >>>>>>>>>>>>>> hardwire any solver parameters in the code with, like, >>>>>>>>>>>>>> KSPSetXXX() or PCSetXXX() Please send all of them. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Something funky definitely happened when the true residual >>>>>>>>>>>>>> norms jumped up. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Could you run the same thing with -ksp_view and don't use any >>>>>>>>>>>>>> thing like -ksp_error_if_not_converged so we can see exactly >>>>>>>>>>>>>> what is being run. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Barry >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>>> On May 22, 2024, at 3:21 PM, Colton Bryant >>>>>>>>>>>>>>> <[email protected] >>>>>>>>>>>>>>> <mailto:[email protected]>> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> This Message Is From an External Sender >>>>>>>>>>>>>>> This message came from outside your organization. >>>>>>>>>>>>>>> Hello, >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> I am solving the Stokes equations on a MAC grid discretized by >>>>>>>>>>>>>>> finite differences using a DMSTAG object. I have tested the >>>>>>>>>>>>>>> solver quite extensively on manufactured problems and it seems >>>>>>>>>>>>>>> to work well. As I am still just trying to get things working >>>>>>>>>>>>>>> and not yet worried about speed I am using the following solver >>>>>>>>>>>>>>> options: >>>>>>>>>>>>>>> -pc_type fieldsplit >>>>>>>>>>>>>>> -pc_fieldsplit_detect_saddle_point >>>>>>>>>>>>>>> -fieldsplit_0_pc_type lu >>>>>>>>>>>>>>> -fieldsplit_1_ksp_rtol 1.e-8 >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> However I am now using this solver as an inner step of a larger >>>>>>>>>>>>>>> code and have run into issues. The code repeatedly solves the >>>>>>>>>>>>>>> Stokes equations with varying right hand sides coming from >>>>>>>>>>>>>>> changing problem geometry (the solver is a part of an overset >>>>>>>>>>>>>>> grid scheme coupled to a level set method evolving in time). >>>>>>>>>>>>>>> After a couple timesteps I observe the following output when >>>>>>>>>>>>>>> running with -fieldsplit_1_ksp_converged_reason >>>>>>>>>>>>>>> -fieldsplit_1_ksp_monitor_true_residual: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Residual norms for back_fieldsplit_1_ solve. >>>>>>>>>>>>>>> 0 KSP preconditioned resid norm 2.826514299465e-02 true >>>>>>>>>>>>>>> resid norm 2.826514299465e-02 ||r(i)||/||b|| 1.000000000000e+00 >>>>>>>>>>>>>>> 1 KSP preconditioned resid norm 7.286621865915e-03 true >>>>>>>>>>>>>>> resid norm 7.286621865915e-03 ||r(i)||/||b|| 2.577953300039e-01 >>>>>>>>>>>>>>> 2 KSP preconditioned resid norm 1.500598474492e-03 true >>>>>>>>>>>>>>> resid norm 1.500598474492e-03 ||r(i)||/||b|| 5.309007192273e-02 >>>>>>>>>>>>>>> 3 KSP preconditioned resid norm 3.796396924978e-04 true >>>>>>>>>>>>>>> resid norm 3.796396924978e-04 ||r(i)||/||b|| 1.343137349666e-02 >>>>>>>>>>>>>>> 4 KSP preconditioned resid norm 8.091057439816e-05 true >>>>>>>>>>>>>>> resid norm 8.091057439816e-05 ||r(i)||/||b|| 2.862556697960e-03 >>>>>>>>>>>>>>> 5 KSP preconditioned resid norm 3.689113122359e-05 true >>>>>>>>>>>>>>> resid norm 3.689113122359e-05 ||r(i)||/||b|| 1.305181128239e-03 >>>>>>>>>>>>>>> 6 KSP preconditioned resid norm 2.116450533352e-05 true >>>>>>>>>>>>>>> resid norm 2.116450533352e-05 ||r(i)||/||b|| 7.487846545662e-04 >>>>>>>>>>>>>>> 7 KSP preconditioned resid norm 3.968234031201e-06 true >>>>>>>>>>>>>>> resid norm 3.968234031200e-06 ||r(i)||/||b|| 1.403932055801e-04 >>>>>>>>>>>>>>> 8 KSP preconditioned resid norm 6.666949419511e-07 true >>>>>>>>>>>>>>> resid norm 6.666949419506e-07 ||r(i)||/||b|| 2.358717739644e-05 >>>>>>>>>>>>>>> 9 KSP preconditioned resid norm 1.941522884928e-07 true >>>>>>>>>>>>>>> resid norm 1.941522884931e-07 ||r(i)||/||b|| 6.868965372998e-06 >>>>>>>>>>>>>>> 10 KSP preconditioned resid norm 6.729545258682e-08 true >>>>>>>>>>>>>>> resid norm 6.729545258626e-08 ||r(i)||/||b|| 2.380863687793e-06 >>>>>>>>>>>>>>> 11 KSP preconditioned resid norm 3.009070131709e-08 true >>>>>>>>>>>>>>> resid norm 3.009070131735e-08 ||r(i)||/||b|| 1.064586912687e-06 >>>>>>>>>>>>>>> 12 KSP preconditioned resid norm 7.849353009588e-09 true >>>>>>>>>>>>>>> resid norm 7.849353009903e-09 ||r(i)||/||b|| 2.777043445840e-07 >>>>>>>>>>>>>>> 13 KSP preconditioned resid norm 2.306283345754e-09 true >>>>>>>>>>>>>>> resid norm 2.306283346677e-09 ||r(i)||/||b|| 8.159461097060e-08 >>>>>>>>>>>>>>> 14 KSP preconditioned resid norm 9.336302495083e-10 true >>>>>>>>>>>>>>> resid norm 9.336302502503e-10 ||r(i)||/||b|| 3.303115255517e-08 >>>>>>>>>>>>>>> 15 KSP preconditioned resid norm 6.537456143401e-10 true >>>>>>>>>>>>>>> resid norm 6.537456141617e-10 ||r(i)||/||b|| 2.312903968982e-08 >>>>>>>>>>>>>>> 16 KSP preconditioned resid norm 6.389159552788e-10 true >>>>>>>>>>>>>>> resid norm 6.389159550304e-10 ||r(i)||/||b|| 2.260437724130e-08 >>>>>>>>>>>>>>> 17 KSP preconditioned resid norm 6.380905134246e-10 true >>>>>>>>>>>>>>> resid norm 6.380905136023e-10 ||r(i)||/||b|| 2.257517372981e-08 >>>>>>>>>>>>>>> 18 KSP preconditioned resid norm 6.380440605992e-10 true >>>>>>>>>>>>>>> resid norm 6.380440604688e-10 ||r(i)||/||b|| 2.257353025207e-08 >>>>>>>>>>>>>>> 19 KSP preconditioned resid norm 6.380427156582e-10 true >>>>>>>>>>>>>>> resid norm 6.380427157894e-10 ||r(i)||/||b|| 2.257348267830e-08 >>>>>>>>>>>>>>> 20 KSP preconditioned resid norm 6.380426714897e-10 true >>>>>>>>>>>>>>> resid norm 6.380426714004e-10 ||r(i)||/||b|| 2.257348110785e-08 >>>>>>>>>>>>>>> 21 KSP preconditioned resid norm 6.380426656970e-10 true >>>>>>>>>>>>>>> resid norm 6.380426658839e-10 ||r(i)||/||b|| 2.257348091268e-08 >>>>>>>>>>>>>>> 22 KSP preconditioned resid norm 6.380426650538e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650287e-10 ||r(i)||/||b|| 2.257348088242e-08 >>>>>>>>>>>>>>> 23 KSP preconditioned resid norm 6.380426649918e-10 true >>>>>>>>>>>>>>> resid norm 6.380426645888e-10 ||r(i)||/||b|| 2.257348086686e-08 >>>>>>>>>>>>>>> 24 KSP preconditioned resid norm 6.380426649803e-10 true >>>>>>>>>>>>>>> resid norm 6.380426644294e-10 ||r(i)||/||b|| 2.257348086122e-08 >>>>>>>>>>>>>>> 25 KSP preconditioned resid norm 6.380426649796e-10 true >>>>>>>>>>>>>>> resid norm 6.380426649774e-10 ||r(i)||/||b|| 2.257348088061e-08 >>>>>>>>>>>>>>> 26 KSP preconditioned resid norm 6.380426649795e-10 true >>>>>>>>>>>>>>> resid norm 6.380426653788e-10 ||r(i)||/||b|| 2.257348089481e-08 >>>>>>>>>>>>>>> 27 KSP preconditioned resid norm 6.380426649795e-10 true >>>>>>>>>>>>>>> resid norm 6.380426646744e-10 ||r(i)||/||b|| 2.257348086989e-08 >>>>>>>>>>>>>>> 28 KSP preconditioned resid norm 6.380426649795e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650818e-10 ||r(i)||/||b|| 2.257348088430e-08 >>>>>>>>>>>>>>> 29 KSP preconditioned resid norm 6.380426649795e-10 true >>>>>>>>>>>>>>> resid norm 6.380426649518e-10 ||r(i)||/||b|| 2.257348087970e-08 >>>>>>>>>>>>>>> 30 KSP preconditioned resid norm 6.380426652142e-10 true >>>>>>>>>>>>>>> resid norm 6.380426652142e-10 ||r(i)||/||b|| 2.257348088898e-08 >>>>>>>>>>>>>>> 31 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426646799e-10 ||r(i)||/||b|| 2.257348087008e-08 >>>>>>>>>>>>>>> 32 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426648077e-10 ||r(i)||/||b|| 2.257348087460e-08 >>>>>>>>>>>>>>> 33 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426649048e-10 ||r(i)||/||b|| 2.257348087804e-08 >>>>>>>>>>>>>>> 34 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426648142e-10 ||r(i)||/||b|| 2.257348087483e-08 >>>>>>>>>>>>>>> 35 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426651079e-10 ||r(i)||/||b|| 2.257348088522e-08 >>>>>>>>>>>>>>> 36 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650433e-10 ||r(i)||/||b|| 2.257348088294e-08 >>>>>>>>>>>>>>> 37 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426649765e-10 ||r(i)||/||b|| 2.257348088057e-08 >>>>>>>>>>>>>>> 38 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650364e-10 ||r(i)||/||b|| 2.257348088269e-08 >>>>>>>>>>>>>>> 39 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650051e-10 ||r(i)||/||b|| 2.257348088159e-08 >>>>>>>>>>>>>>> 40 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426651154e-10 ||r(i)||/||b|| 2.257348088549e-08 >>>>>>>>>>>>>>> 41 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650246e-10 ||r(i)||/||b|| 2.257348088227e-08 >>>>>>>>>>>>>>> 42 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650702e-10 ||r(i)||/||b|| 2.257348088389e-08 >>>>>>>>>>>>>>> 43 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426651686e-10 ||r(i)||/||b|| 2.257348088737e-08 >>>>>>>>>>>>>>> 44 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650870e-10 ||r(i)||/||b|| 2.257348088448e-08 >>>>>>>>>>>>>>> 45 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426651208e-10 ||r(i)||/||b|| 2.257348088568e-08 >>>>>>>>>>>>>>> 46 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426651441e-10 ||r(i)||/||b|| 2.257348088650e-08 >>>>>>>>>>>>>>> 47 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650955e-10 ||r(i)||/||b|| 2.257348088478e-08 >>>>>>>>>>>>>>> 48 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650877e-10 ||r(i)||/||b|| 2.257348088451e-08 >>>>>>>>>>>>>>> 49 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426651240e-10 ||r(i)||/||b|| 2.257348088579e-08 >>>>>>>>>>>>>>> 50 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426650534e-10 ||r(i)||/||b|| 2.257348088329e-08 >>>>>>>>>>>>>>> 51 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426648615e-10 ||r(i)||/||b|| 2.257348087651e-08 >>>>>>>>>>>>>>> 52 KSP preconditioned resid norm 6.380426652141e-10 true >>>>>>>>>>>>>>> resid norm 6.380426649523e-10 ||r(i)||/||b|| 2.257348087972e-08 >>>>>>>>>>>>>>> 53 KSP preconditioned resid norm 6.380426652140e-10 true >>>>>>>>>>>>>>> resid norm 6.380426652601e-10 ||r(i)||/||b|| 2.257348089061e-08 >>>>>>>>>>>>>>> 54 KSP preconditioned resid norm 6.380426652125e-10 true >>>>>>>>>>>>>>> resid norm 6.380427512852e-10 ||r(i)||/||b|| 2.257348393411e-08 >>>>>>>>>>>>>>> 55 KSP preconditioned resid norm 6.380426651849e-10 true >>>>>>>>>>>>>>> resid norm 6.380603444402e-10 ||r(i)||/||b|| 2.257410636701e-08 >>>>>>>>>>>>>>> 56 KSP preconditioned resid norm 6.380426646751e-10 true >>>>>>>>>>>>>>> resid norm 6.439925413105e-10 ||r(i)||/||b|| 2.278398313542e-08 >>>>>>>>>>>>>>> 57 KSP preconditioned resid norm 6.380426514019e-10 true >>>>>>>>>>>>>>> resid norm 2.674218007058e-09 ||r(i)||/||b|| 9.461186902765e-08 >>>>>>>>>>>>>>> 58 KSP preconditioned resid norm 6.380425077384e-10 true >>>>>>>>>>>>>>> resid norm 2.406759314486e-08 ||r(i)||/||b|| 8.514937691775e-07 >>>>>>>>>>>>>>> 59 KSP preconditioned resid norm 6.380406171326e-10 true >>>>>>>>>>>>>>> resid norm 3.100137288622e-07 ||r(i)||/||b|| 1.096805803957e-05 >>>>>>>>>>>>>>> Linear back_fieldsplit_1_ solve did not converge due to >>>>>>>>>>>>>>> DIVERGED_BREAKDOWN iterations 60 >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Any advice on steps I could take to elucidate the issue would >>>>>>>>>>>>>>> be greatly appreciated. Thanks so much for any help in advance! >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Best, >>>>>>>>>>>>>>> Colton Bryant >>>>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>> >>>>>>>> >>>>>> >>>> >>
