Hmm,

   Ok you can try running it directly in the debugger since it is one process, 
type

  gdb ./blowup_batch_refine

  then 

  when the debugger comes up (if it does not cut and paste all output and send 
it)

  run -on_error_abort -snes_mf_operator  and any other options you normally use


  Barry

> On Sep 7, 2015, at 8:18 PM, Gideon Simpson <[email protected]> wrote:
> 
> Running with that flag gives me this:
> 
> [0]PETSC ERROR: PETSC: Attaching gdb to ./blowup_batch_refine of pid 16111 on 
> gs_air
> Unable to start debugger: No such file or directory
> 
> 
> 
> -gideon
> 
>> On Sep 7, 2015, at 9:11 PM, Barry Smith <[email protected]> wrote:
>> 
>> 
>>  This should not happen. Run with a debug version of PETSc installed and the 
>> option -start_in_debugger noxterm  Once the debugger starts up type cont and 
>> when it crashes type where or bt  Send all output
>> 
>> 
>> 
>>  Barry
>> 
>> 
>>> On Sep 7, 2015, at 8:09 PM, Gideon Simpson <[email protected]> wrote:
>>> 
>>> I’m getting an error with -snes_mf_operator, 
>>> 
>>>  0 SNES Function norm 1.421454390131e-02 
>>> [0]PETSC ERROR: 
>>> ------------------------------------------------------------------------
>>> [0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, 
>>> probably memory access out of range
>>> [0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
>>> [0]PETSC ERROR: or see 
>>> http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind
>>> [0]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X 
>>> to find memory corruption errors
>>> [0]PETSC ERROR: configure using --with-debugging=yes, recompile, link, and 
>>> run 
>>> [0]PETSC ERROR: to get more information on the crash.
>>> [0]PETSC ERROR: --------------------- Error Message 
>>> --------------------------------------------------------------
>>> [0]PETSC ERROR: Signal received
>>> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for 
>>> trouble shooting.
>>> [0]PETSC ERROR: Petsc Release Version 3.5.3, unknown 
>>> [0]PETSC ERROR: ./blowup_batch_refine on a arch-macports named gs_air by 
>>> gideon Mon Sep  7 21:08:19 2015
>>> [0]PETSC ERROR: Configure options --prefix=/opt/local 
>>> --prefix=/opt/local/lib/petsc --with-valgrind=0 --with-shared-libraries 
>>> --with-debugging=0 --with-c2html-dir=/opt/local --with-x=0 
>>> --with-blas-lapack-lib=/System/Library/Frameworks/Accelerate.framework/Versions/Current/Accelerate
>>>  --with-hwloc-dir=/opt/local --with-suitesparse-dir=/opt/local 
>>> --with-superlu-dir=/opt/local --with-metis-dir=/opt/local 
>>> --with-parmetis-dir=/opt/local --with-scalapack-dir=/opt/local 
>>> --with-mumps-dir=/opt/local --with-superlu_dist-dir=/opt/local 
>>> CC=/opt/local/bin/mpicc-mpich-mp CXX=/opt/local/bin/mpicxx-mpich-mp 
>>> FC=/opt/local/bin/mpif90-mpich-mp F77=/opt/local/bin/mpif90-mpich-mp 
>>> F90=/opt/local/bin/mpif90-mpich-mp COPTFLAGS=-Os CXXOPTFLAGS=-Os 
>>> FOPTFLAGS=-Os LDFLAGS="-L/opt/local/lib -Wl,-headerpad_max_install_names" 
>>> CPPFLAGS=-I/opt/local/include CFLAGS="-Os -arch x86_64" CXXFLAGS=-Os 
>>> FFLAGS=-Os FCFLAGS=-Os F90FLAGS=-Os PETSC_ARCH=arch-macports 
>>> --with-mpiexec=mpiexec-mpich-mp
>>> [0]PETSC ERROR: #1 User provided function() line 0 in  unknown file
>>> application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0
>>> 
>>> -gideon
>>> 
>>>> On Sep 7, 2015, at 9:01 PM, Barry Smith <[email protected]> wrote:
>>>> 
>>>> 
>>>> My guess is the Jacobian is not correct (or correct "enough"), hence PETSc 
>>>> SNES is generating a poor descent direction. You can try 
>>>> -snes_mf_operator -ksp_monitor_true residual as additional arguments. What 
>>>> happens?
>>>> 
>>>> Barry
>>>> 
>>>> 
>>>> 
>>>>> On Sep 7, 2015, at 7:49 PM, Gideon Simpson <[email protected]> 
>>>>> wrote:
>>>>> 
>>>>> No problem Matt, I don’t think we had previously discussed that output.  
>>>>> Here is a case where things fail.
>>>>> 
>>>>>     0 SNES Function norm 4.027481756921e-09 
>>>>>     1 SNES Function norm 1.760477878365e-12 
>>>>>   Nonlinear solve converged due to CONVERGED_SNORM_RELATIVE iterations 1
>>>>>   0 SNES Function norm 5.066222213176e+03 
>>>>>   1 SNES Function norm 8.484697184230e+02 
>>>>>   2 SNES Function norm 6.549559723294e+02 
>>>>>   3 SNES Function norm 5.770723278153e+02 
>>>>>   4 SNES Function norm 5.237702240594e+02 
>>>>>   5 SNES Function norm 4.753909019848e+02 
>>>>>   6 SNES Function norm 4.221784590755e+02 
>>>>>   7 SNES Function norm 3.806525080483e+02 
>>>>>   8 SNES Function norm 3.762054656019e+02 
>>>>>   9 SNES Function norm 3.758975226873e+02 
>>>>>  10 SNES Function norm 3.757032042706e+02 
>>>>>  11 SNES Function norm 3.728798164234e+02 
>>>>>  12 SNES Function norm 3.723078741075e+02 
>>>>>  13 SNES Function norm 3.721848059825e+02 
>>>>>  14 SNES Function norm 3.720227575629e+02 
>>>>>  15 SNES Function norm 3.720051998555e+02 
>>>>>  16 SNES Function norm 3.718945430587e+02 
>>>>>  17 SNES Function norm 3.700412694044e+02 
>>>>>  18 SNES Function norm 3.351964889461e+02 
>>>>>  19 SNES Function norm 3.096016086233e+02 
>>>>>  20 SNES Function norm 3.008410789787e+02 
>>>>>  21 SNES Function norm 2.752316716557e+02 
>>>>>  22 SNES Function norm 2.707658474165e+02 
>>>>>  23 SNES Function norm 2.698436736049e+02 
>>>>>  24 SNES Function norm 2.618233857172e+02 
>>>>>  25 SNES Function norm 2.600121920634e+02 
>>>>>  26 SNES Function norm 2.585046423168e+02 
>>>>>  27 SNES Function norm 2.568551090220e+02 
>>>>>  28 SNES Function norm 2.556404537064e+02 
>>>>>  29 SNES Function norm 2.536353523683e+02 
>>>>>  30 SNES Function norm 2.533596070171e+02 
>>>>>  31 SNES Function norm 2.532324379596e+02 
>>>>>  32 SNES Function norm 2.531842335211e+02 
>>>>>  33 SNES Function norm 2.531684527520e+02 
>>>>>  34 SNES Function norm 2.531637604618e+02 
>>>>>  35 SNES Function norm 2.531624767821e+02 
>>>>>  36 SNES Function norm 2.531621359093e+02 
>>>>>  37 SNES Function norm 2.531620504925e+02 
>>>>>  38 SNES Function norm 2.531620350055e+02 
>>>>>  39 SNES Function norm 2.531620310522e+02 
>>>>>  40 SNES Function norm 2.531620300471e+02 
>>>>>  41 SNES Function norm 2.531620298084e+02 
>>>>>  42 SNES Function norm 2.531620297478e+02 
>>>>>  43 SNES Function norm 2.531620297324e+02 
>>>>>  44 SNES Function norm 2.531620297303e+02 
>>>>>  45 SNES Function norm 2.531620297302e+02 
>>>>> Nonlinear solve did not converge due to DIVERGED_LINE_SEARCH iterations 45
>>>>> 0 SNES Function norm 9.636339304380e+03 
>>>>> 1 SNES Function norm 8.997731184634e+03 
>>>>> 2 SNES Function norm 8.120498349232e+03 
>>>>> 3 SNES Function norm 7.322379894820e+03 
>>>>> 4 SNES Function norm 6.599581599149e+03 
>>>>> 5 SNES Function norm 6.374872854688e+03 
>>>>> 6 SNES Function norm 6.372518007653e+03 
>>>>> 7 SNES Function norm 6.073996314301e+03 
>>>>> 8 SNES Function norm 5.635965277054e+03 
>>>>> 9 SNES Function norm 5.155389064046e+03 
>>>>> 10 SNES Function norm 5.080567902638e+03 
>>>>> 11 SNES Function norm 5.058878643969e+03 
>>>>> 12 SNES Function norm 5.058835649793e+03 
>>>>> 13 SNES Function norm 5.058491285707e+03 
>>>>> 14 SNES Function norm 5.057452865337e+03 
>>>>> 15 SNES Function norm 5.057226140688e+03 
>>>>> 16 SNES Function norm 5.056651272898e+03 
>>>>> 17 SNES Function norm 5.056575190057e+03 
>>>>> 18 SNES Function norm 5.056574632598e+03 
>>>>> 19 SNES Function norm 5.056574520229e+03 
>>>>> 20 SNES Function norm 5.056574492569e+03 
>>>>> 21 SNES Function norm 5.056574485124e+03 
>>>>> 22 SNES Function norm 5.056574483029e+03 
>>>>> 23 SNES Function norm 5.056574482427e+03 
>>>>> 24 SNES Function norm 5.056574482302e+03 
>>>>> 25 SNES Function norm 5.056574482287e+03 
>>>>> 26 SNES Function norm 5.056574482282e+03 
>>>>> 27 SNES Function norm 5.056574482281e+03 
>>>>> Nonlinear solve did not converge due to DIVERGED_LINE_SEARCH iterations 27
>>>>> SNES Object: 1 MPI processes
>>>>> type: newtonls
>>>>> maximum iterations=50, maximum function evaluations=10000
>>>>> tolerances: relative=1e-08, absolute=1e-50, solution=1e-08
>>>>> total number of linear solver iterations=28
>>>>> total number of function evaluations=323
>>>>> total number of grid sequence refinements=2
>>>>> SNESLineSearch Object:   1 MPI processes
>>>>>   type: bt
>>>>>     interpolation: cubic
>>>>>     alpha=1.000000e-04
>>>>>   maxstep=1.000000e+08, minlambda=1.000000e-12
>>>>>   tolerances: relative=1.000000e-08, absolute=1.000000e-15, 
>>>>> lambda=1.000000e-08
>>>>>   maximum iterations=40
>>>>> KSP Object:   1 MPI processes
>>>>>   type: gmres
>>>>>     GMRES: restart=30, using Classical (unmodified) Gram-Schmidt 
>>>>> Orthogonalization with no iterative refinement
>>>>>     GMRES: 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:   1 MPI processes
>>>>>   type: lu
>>>>>     LU: out-of-place factorization
>>>>>     tolerance for zero pivot 2.22045e-14
>>>>>     matrix ordering: nd
>>>>>     factor fill ratio given 0, needed 0
>>>>>       Factored matrix follows:
>>>>>         Mat Object:           1 MPI processes
>>>>>           type: seqaij
>>>>>           rows=15991, cols=15991
>>>>>           package used to perform factorization: mumps
>>>>>           total: nonzeros=255801, allocated nonzeros=255801
>>>>>           total number of mallocs used during MatSetValues calls =0
>>>>>             MUMPS run parameters:
>>>>>               SYM (matrix type):                   0 
>>>>>               PAR (host participation):            1 
>>>>>               ICNTL(1) (output for error):         6 
>>>>>               ICNTL(2) (output of diagnostic msg): 0 
>>>>>               ICNTL(3) (output for global info):   0 
>>>>>               ICNTL(4) (level of printing):        0 
>>>>>               ICNTL(5) (input mat struct):         0 
>>>>>               ICNTL(6) (matrix prescaling):        7 
>>>>>               ICNTL(7) (sequentia matrix ordering):6 
>>>>>               ICNTL(8) (scalling strategy):        77 
>>>>>               ICNTL(10) (max num of refinements):  0 
>>>>>               ICNTL(11) (error analysis):          0 
>>>>>               ICNTL(12) (efficiency control):                         1 
>>>>>               ICNTL(13) (efficiency control):                         0 
>>>>>               ICNTL(14) (percentage of estimated workspace increase): 20 
>>>>>               ICNTL(18) (input mat struct):                           0 
>>>>>               ICNTL(19) (Shur complement info):                       0 
>>>>>               ICNTL(20) (rhs sparse pattern):                         0 
>>>>>               ICNTL(21) (somumpstion struct):                            
>>>>> 0 
>>>>>               ICNTL(22) (in-core/out-of-core facility):               0 
>>>>>               ICNTL(23) (max size of memory can be allocated locally):0 
>>>>>               ICNTL(24) (detection of null pivot rows):               0 
>>>>>               ICNTL(25) (computation of a null space basis):          0 
>>>>>               ICNTL(26) (Schur options for rhs or solution):          0 
>>>>>               ICNTL(27) (experimental parameter):                     -8 
>>>>>               ICNTL(28) (use parallel or sequential ordering):        1 
>>>>>               ICNTL(29) (parallel ordering):                          0 
>>>>>               ICNTL(30) (user-specified set of entries in inv(A)):    0 
>>>>>               ICNTL(31) (factors is discarded in the solve phase):    0 
>>>>>               ICNTL(33) (compute determinant):                        0 
>>>>>               CNTL(1) (relative pivoting threshold):      0.01 
>>>>>               CNTL(2) (stopping criterion of refinement): 1.49012e-08 
>>>>>               CNTL(3) (absomumpste pivoting threshold):      0 
>>>>>               CNTL(4) (vamumpse of static pivoting):         -1 
>>>>>               CNTL(5) (fixation for null pivots):         0 
>>>>>               RINFO(1) (local estimated flops for the elimination after 
>>>>> analysis): 
>>>>>                 [0] 1.95838e+06 
>>>>>               RINFO(2) (local estimated flops for the assembly after 
>>>>> factorization): 
>>>>>                 [0]  143924 
>>>>>               RINFO(3) (local estimated flops for the elimination after 
>>>>> factorization): 
>>>>>                 [0]  1.95943e+06 
>>>>>               INFO(15) (estimated size of (in MB) MUMPS internal data for 
>>>>> running numerical factorization): 
>>>>>               [0] 7 
>>>>>               INFO(16) (size of (in MB) MUMPS internal data used during 
>>>>> numerical factorization): 
>>>>>                 [0] 7 
>>>>>               INFO(23) (num of pivots eliminated on this processor after 
>>>>> factorization): 
>>>>>                 [0] 15991 
>>>>>               RINFOG(1) (global estimated flops for the elimination after 
>>>>> analysis): 1.95838e+06 
>>>>>               RINFOG(2) (global estimated flops for the assembly after 
>>>>> factorization): 143924 
>>>>>               RINFOG(3) (global estimated flops for the elimination after 
>>>>> factorization): 1.95943e+06 
>>>>>               (RINFOG(12) RINFOG(13))*2^INFOG(34) (determinant): 
>>>>> (0,0)*(2^0)
>>>>>               INFOG(3) (estimated real workspace for factors on all 
>>>>> processors after analysis): 255801 
>>>>>               INFOG(4) (estimated integer workspace for factors on all 
>>>>> processors after analysis): 127874 
>>>>>               INFOG(5) (estimated maximum front size in the complete 
>>>>> tree): 11 
>>>>>               INFOG(6) (number of nodes in the complete tree): 3996 
>>>>>               INFOG(7) (ordering option effectively use after analysis): 
>>>>> 6 
>>>>>               INFOG(8) (structural symmetry in percent of the permuted 
>>>>> matrix after analysis): 86 
>>>>>               INFOG(9) (total real/complex workspace to store the matrix 
>>>>> factors after factorization): 255865 
>>>>>               INFOG(10) (total integer space store the matrix factors 
>>>>> after factorization): 127890 
>>>>>               INFOG(11) (order of largest frontal matrix after 
>>>>> factorization): 11 
>>>>>               INFOG(12) (number of off-diagonal pivots): 19 
>>>>>               INFOG(13) (number of delayed pivots after factorization): 8 
>>>>>               INFOG(14) (number of memory compress after factorization): 
>>>>> 0 
>>>>>               INFOG(15) (number of steps of iterative refinement after 
>>>>> solution): 0 
>>>>>               INFOG(16) (estimated size (in MB) of all MUMPS internal 
>>>>> data for factorization after analysis: value on the most memory consuming 
>>>>> processor): 7 
>>>>>               INFOG(17) (estimated size of all MUMPS internal data for 
>>>>> factorization after analysis: sum over all processors): 7 
>>>>>               INFOG(18) (size of all MUMPS internal data allocated during 
>>>>> factorization: value on the most memory consuming processor): 7 
>>>>>               INFOG(19) (size of all MUMPS internal data allocated during 
>>>>> factorization: sum over all processors): 7 
>>>>>               INFOG(20) (estimated number of entries in the factors): 
>>>>> 255801 
>>>>>               INFOG(21) (size in MB of memory effectively used during 
>>>>> factorization - value on the most memory consuming processor): 7 
>>>>>               INFOG(22) (size in MB of memory effectively used during 
>>>>> factorization - sum over all processors): 7 
>>>>>               INFOG(23) (after analysis: value of ICNTL(6) effectively 
>>>>> used): 0 
>>>>>               INFOG(24) (after analysis: value of ICNTL(12) effectively 
>>>>> used): 1 
>>>>>               INFOG(25) (after factorization: number of pivots modified 
>>>>> by static pivoting): 0 
>>>>>               INFOG(28) (after factorization: number of null pivots 
>>>>> encountered): 0
>>>>>               INFOG(29) (after factorization: effective number of entries 
>>>>> in the factors (sum over all processors)): 255865
>>>>>               INFOG(30, 31) (after solution: size in Mbytes of memory 
>>>>> used during solution phase): 5, 5
>>>>>               INFOG(32) (after analysis: type of analysis done): 1
>>>>>               INFOG(33) (value used for ICNTL(8)): 7
>>>>>               INFOG(34) (exponent of the determinant if determinant is 
>>>>> requested): 0
>>>>>   linear system matrix = precond matrix:
>>>>>   Mat Object:     1 MPI processes
>>>>>     type: seqaij
>>>>>     rows=15991, cols=15991
>>>>>     total: nonzeros=223820, allocated nonzeros=431698
>>>>>     total number of mallocs used during MatSetValues calls =15991
>>>>>       using I-node routines: found 4000 nodes, limit used is 5
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> -gideon
>>>>> 
>>>>>> On Sep 7, 2015, at 8:40 PM, Matthew Knepley <[email protected]> wrote:
>>>>>> 
>>>>>> On Mon, Sep 7, 2015 at 7:32 PM, Gideon Simpson 
>>>>>> <[email protected]> wrote:
>>>>>> Barry,
>>>>>> 
>>>>>> I finally got a chance to really try using the grid sequencing within my 
>>>>>> code.  I find that, in some cases, even if it can solve successfully on 
>>>>>> the coarsest mesh, the SNES fails, usually due to a line search failure, 
>>>>>> when it tries to compute along the grid sequence.  Would you have any 
>>>>>> suggestions?
>>>>>> 
>>>>>> I apologize if I have asked before, but can you give me -snes_view for 
>>>>>> the solver? I could not find it in the email thread.
>>>>>> 
>>>>>> I would suggest trying to fiddle with the line search, or precondition 
>>>>>> it with Richardson. It would be nice to see -snes_monitor
>>>>>> for the runs that fail, and then we can break down the residual into 
>>>>>> fields and look at it again (if my custom residual monitor
>>>>>> does not work we can write one easily). Seeing which part of the 
>>>>>> residual does not converge is key to designing the NASM
>>>>>> for the problem. I have just seen the virtuoso of this, Xiao-Chuan Cai, 
>>>>>> present it. We need better monitoring in PETSc.
>>>>>> 
>>>>>> Thanks,
>>>>>> 
>>>>>>   Matt
>>>>>> 
>>>>>> -gideon
>>>>>> 
>>>>>>> On Aug 28, 2015, at 4:21 PM, Barry Smith <[email protected]> wrote:
>>>>>>> 
>>>>>>> 
>>>>>>>> On Aug 28, 2015, at 3:04 PM, Gideon Simpson <[email protected]> 
>>>>>>>> wrote:
>>>>>>>> 
>>>>>>>> Yes, if i continue in this parameter on the coarse mesh, I can 
>>>>>>>> generally solve at all values. I do find that I need to do some amount 
>>>>>>>> of continuation to solve near the endpoint.  The problem is that on 
>>>>>>>> the coarse mesh, things are not fully resolved at all the values along 
>>>>>>>> the continuation parameter, and I would like to do refinement.  
>>>>>>>> 
>>>>>>>> One subtlety is that I actually want the intermediate continuation 
>>>>>>>> solutions  too.  Currently, without doing any grid sequence, I compute 
>>>>>>>> each, write it to disk, and then go on to the next one.  So I now need 
>>>>>>>> to go back an refine them.  I was thinking that perhaps I could refine 
>>>>>>>> them on the fly, dump them to disk, and use the coarse solution as the 
>>>>>>>> starting guess at the next iteration, but that would seem to require 
>>>>>>>> resetting the snes back to the coarse grid.
>>>>>>>> 
>>>>>>>> The alternative would be to just script the mesh refinement in a post 
>>>>>>>> processing stage, where each value of the continuation is parameter is 
>>>>>>>> loaded on the coarse mesh, and refined.  Perhaps that’s the most 
>>>>>>>> practical thing to do.
>>>>>>> 
>>>>>>> I would do the following. Create your DM and create a SNES that will do 
>>>>>>> the continuation
>>>>>>> 
>>>>>>> loop over continuation parameter
>>>>>>> 
>>>>>>>      SNESSolve(snes,NULL,Ucoarse);
>>>>>>> 
>>>>>>>      if (you decide you want to see the refined solution at this 
>>>>>>> continuation point) {
>>>>>>>           SNESCreate(comm,&snesrefine);
>>>>>>>           SNESSetDM()
>>>>>>>           etc
>>>>>>>           SNESSetGridSequence(snesrefine,)
>>>>>>>           SNESSolve(snesrefine,0,Ucoarse);
>>>>>>>           SNESGetSolution(snesrefine,&Ufine);
>>>>>>>           VecView(Ufine or do whatever you want to do with the Ufine at 
>>>>>>> that continuation point
>>>>>>>           SNESDestroy(snesrefine);
>>>>>>>     end if
>>>>>>> 
>>>>>>> end loop over continuation parameter.
>>>>>>> 
>>>>>>> Barry
>>>>>>> 
>>>>>>>> 
>>>>>>>> -gideon
>>>>>>>> 
>>>>>>>>> On Aug 28, 2015, at 3:55 PM, Barry Smith <[email protected]> wrote:
>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 
>>>>>>>>>> 3.  This problem is actually part of a continuation problem that 
>>>>>>>>>> roughly looks like this 
>>>>>>>>>> 
>>>>>>>>>> for( continuation parameter p = 0 to 1){
>>>>>>>>>> 
>>>>>>>>>>      solve with parameter p_i using solution from p_{i-1},
>>>>>>>>>> }
>>>>>>>>>> 
>>>>>>>>>> What I would like to do is to start the solver, for each value of 
>>>>>>>>>> parameter p_i on the coarse mesh, and then do grid sequencing on 
>>>>>>>>>> that.  But it appears that after doing grid sequencing on the 
>>>>>>>>>> initial p_0 = 0, the SNES is set to use the finer mesh.
>>>>>>>>> 
>>>>>>>>> So you are using continuation to give you a good enough initial guess 
>>>>>>>>> on the coarse level to even get convergence on the coarse level? 
>>>>>>>>> First I would check if you even need the continuation (or can you not 
>>>>>>>>> even solve the coarse problem without it).
>>>>>>>>> 
>>>>>>>>> If you do need the continuation then you will need to tweak how you 
>>>>>>>>> do the grid sequencing. I think this will work: 
>>>>>>>>> 
>>>>>>>>> Do not use -snes_grid_sequencing  
>>>>>>>>> 
>>>>>>>>> Run SNESSolve() as many times as you want with your continuation 
>>>>>>>>> parameter. This will all happen on the coarse mesh.
>>>>>>>>> 
>>>>>>>>> Call SNESSetGridSequence()
>>>>>>>>> 
>>>>>>>>> Then call SNESSolve() again and it will do one solve on the coarse 
>>>>>>>>> level and then interpolate to the next level etc.
>>>>>>>> 
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> -- 
>>>>>> 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
>>>>> 
>>>> 
>>> 
>> 
> 

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