[petsc-users] Diagnosing Convergence Issue in Fieldsplit Problem
Colton Bryant
coltonbryant2021 at u.northwestern.edu
Thu May 30 15:49:28 CDT 2024
Hi Barry,
Yes, each index set has the correct entries when I checked manually on a
small example.
For the nullspace I was trying to manually build the constant basis on a
compatible DMStag containing just the pressure nodes and creating the
nullspace from that but that does not seem to work. Using
MatNullSpaceCreate(comm,PETSC_TRUE,0,NULL,&sp) does show that the Schur
system has the attached null space. However the system still fails to
converge with the schur block giving the error
Linear fieldsplit_pressure_ solve did not converge due to
DIVERGED_PC_FAILED iterations 0
PC failed due to FACTOR_NUMERIC_ZEROPIVOT
The output from -ksp_view is
KSP Object: 1 MPI process
type: fgmres
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-12, absolute=1e-50, divergence=10000.
right preconditioning
using UNPRECONDITIONED norm type for convergence test
PC Object: 1 MPI process
type: fieldsplit
FieldSplit with Schur preconditioner, factorization FULL
Preconditioner for the Schur complement formed from A11
Split info:
Split number 0 Defined by IS
Split number 1 Defined by IS
KSP solver for A00 block
KSP Object: (fieldsplit_velocity_) 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: (fieldsplit_velocity_) 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 2.17695
Factored matrix follows:
Mat Object: (fieldsplit_velocity_) 1 MPI process
type: seqaij
rows=60, cols=60
package used to perform factorization: petsc
total: nonzeros=1058, allocated nonzeros=1058
using I-node routines: found 35 nodes, limit used is 5
linear system matrix = precond matrix:
Mat Object: (fieldsplit_velocity_) 1 MPI process
type: seqaij
rows=60, cols=60
total: nonzeros=486, allocated nonzeros=486
total number of mallocs used during MatSetValues calls=0
using I-node routines: found 35 nodes, limit used is 5
KSP solver for S = A11 - A10 inv(A00) A01
KSP Object: (fieldsplit_pressure_) 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-12, absolute=1e-50, divergence=10000.
left preconditioning
using PRECONDITIONED norm type for convergence test
PC Object: (fieldsplit_pressure_) 1 MPI process
type: ilu
out-of-place factorization
0 levels of fill
tolerance for zero pivot 2.22045e-14
matrix ordering: natural
factor fill ratio given 1., needed 1.
Factored matrix follows:
Mat Object: (fieldsplit_pressure_) 1 MPI process
type: seqaij
rows=25, cols=25
package used to perform factorization: petsc
total: nonzeros=105, allocated nonzeros=105
not using I-node routines
linear system matrix followed by preconditioner matrix:
Mat Object: (fieldsplit_pressure_) 1 MPI process
type: schurcomplement
rows=25, cols=25
has attached null space
Schur complement A11 - A10 inv(A00) A01
A11
Mat Object: (fieldsplit_pressure_) 1 MPI process
type: seqaij
rows=25, cols=25
total: nonzeros=105, allocated nonzeros=105
total number of mallocs used during MatSetValues calls=0
has attached null space
not using I-node routines
A10
Mat Object: 1 MPI process
type: seqaij
rows=25, cols=60
total: nonzeros=220, allocated nonzeros=220
total number of mallocs used during MatSetValues calls=0
not using I-node routines
KSP solver for A00 block viewable with the additional option
-fieldsplit_velocity_ksp_view
A01
Mat Object: 1 MPI process
type: seqaij
rows=60, cols=25
total: nonzeros=220, allocated nonzeros=220
total number of mallocs used during MatSetValues calls=0
using I-node routines: found 35 nodes, limit used is 5
Mat Object: (fieldsplit_pressure_) 1 MPI process
type: seqaij
rows=25, cols=25
total: nonzeros=105, allocated nonzeros=105
total number of mallocs used during MatSetValues calls=0
has attached null space
not using I-node routines
linear system matrix = precond matrix:
Mat Object: 1 MPI process
type: seqaij
rows=85, cols=85
total: nonzeros=1031, allocated nonzeros=1031
total number of mallocs used during MatSetValues calls=0
has attached null space
using I-node routines: found 35 nodes, limit used is 5
On Thu, May 30, 2024 at 1:53 PM Barry Smith <bsmith at petsc.dev> wrote:
>
>
> On May 30, 2024, at 3:15 PM, Colton Bryant <
> coltonbryant2021 at u.northwestern.edu> 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 <bsmith at petsc.dev> 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 <
>> coltonbryant2021 at u.northwestern.edu> 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 <bsmith at petsc.dev> 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 <
>>> coltonbryant2021 at u.northwestern.edu> 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 <bsmith at petsc.dev> wrote:
>>>
>>>>
>>>>
>>>> Sorry I gave the wrong option. Use -fieldsplit_0_ksp_type preonly
>>>>
>>>> Barry
>>>>
>>>> On May 23, 2024, at 12:51 PM, Colton Bryant <
>>>> coltonbryant2021 at u.northwestern.edu> 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 <bsmith at petsc.dev> wrote:
>>>>
>>>>>
>>>>> Use -pc_fieldsplit_0_ksp_type preonly
>>>>>
>>>>>
>>>>>
>>>>> On May 23, 2024, at 12:43 PM, Colton Bryant <
>>>>> coltonbryant2021 at u.northwestern.edu> 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!bCDy0AGlRVZN8FvclLHSIOHJllbF32aOzCAC9kMvOUhIgbwNdThezxjx_Sdpx4LEVLbq2kqRnyBjFPLl771Z-9CKH4TqCL3Uke1X70RO7aM$ 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 <bsmith at petsc.dev> 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 <
>>>>>> coltonbryant2021 at u.northwestern.edu> 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 <bsmith at petsc.dev> 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 <
>>>>>>> coltonbryant2021 at u.northwestern.edu> 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 <bsmith at petsc.dev>
>>>>>>> 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 <
>>>>>>>> coltonbryant2021 at u.northwestern.edu> 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
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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