[petsc-users] Issue of mg_coarse_ksp not converge

Wenbo Zhao zhaowenbo.npic at gmail.com
Mon Oct 2 10:06:05 CDT 2017


Matt,

Test 1 nonsmooth
zhaowenbo at ubuntu:~/test_slepc/SPARK/spark$ make NCORE=1 runkr_nonsmooth
mpirun -n 1 ./step-41 \
   -st_ksp_type gmres  -st_ksp_view -st_ksp_monitor  \
   -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths 0 \
   -mata AMAT.dat -matb BMAT.dat \
   -eps_nev 1 -eps_ncv 10  -eps_monitor  -log_view > log_nonsmooth 2>&1

Test 2 smooth
zhaowenbo at ubuntu:~/test_slepc/SPARK/spark$ make NCORE=1 runkr_smooth
mpirun -n 1 ./step-41 \
   -st_ksp_type gmres -st_ksp_view -st_ksp_monitor  \
   -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths 1 \
   -mata AMAT.dat -matb BMAT.dat \
   -eps_nev 1 -eps_ncv 10  -eps_monitor -log_view > log_smooth 2>&1
makefile:43: recipe for target 'runkr_smooth' failed
make: *** [runkr_smooth] Error 91


Thanks,

Wenbo

On Mon, Oct 2, 2017 at 10:48 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Mon, Oct 2, 2017 at 10:43 AM, Wenbo Zhao <zhaowenbo.npic at gmail.com>
> wrote:
>
>> Mark,
>>
>> Thanks for your reply.
>>
>> On Mon, Oct 2, 2017 at 9:51 PM, Mark Adams <mfadams at lbl.gov> wrote:
>>
>>> Please send the output with -st_ksp_view and -st_ksp_monitor and we can
>>> start to debug it.
>>>
>>> Test 1 with nonsmooth and preonly is OK
>> zhaowenbo at ubuntu:~/test_slepc/SPARK/spark$ make NCORE=1 runkr_nonsmooth
>> mpirun -n 1 ./step-41 \
>>    -st_ksp_type gmres  -st_ksp_view -st_ksp_monitor  \
>>    -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths 0 \
>>    -st_ksp_view  -mata AMAT.dat -matb BMAT.dat \
>>    -st_mg_coarse_ksp_type preonly   -st_mg_coarse_ksp_monitor  \
>>    -eps_nev 1 -eps_ncv 10  -eps_monitor  -log_view > log_nonsmooth 2>&1
>>
>> Test 2 smooth and preonly is not OK
>> zhaowenbo at ubuntu:~/test_slepc/SPARK/spark$ make NCORE=1 runkr_smooth
>> mpirun -n 1 ./step-41 \
>>    -st_ksp_type gmres -st_ksp_view -st_ksp_monitor  \
>>    -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths 1 \
>>    -st_ksp_view  -mata AMAT.dat -matb BMAT.dat \
>>    -st_mg_coarse_ksp_type preonly   -st_mg_coarse_ksp_monitor  \
>>    -eps_nev 1 -eps_ncv 10  -eps_monitor -log_view > log_smooth 2>&1
>> makefile:43: recipe for target 'runkr_smooth' failed
>> make: *** [runkr_smooth] Error 91
>>
>> Test 3 nonsmooth and gmres is not OK
>> zhaowenbo at ubuntu:~/test_slepc/SPARK/spark$ make NCORE=1 runkr_gmres
>> mpirun -n 1 ./step-41 \
>>    -st_ksp_type gmres  -st_ksp_view -st_ksp_monitor  \
>>    -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths 0 \
>>    -st_ksp_view  -mata AMAT.dat -matb BMAT.dat \
>>    -st_mg_coarse_ksp_type gmres  -st_mg_coarse_ksp_monitor
>> -st_mg_coarse_ksp_rtol 1.0e-6 \
>>
>
> DO NOT DO THIS. Please send the output where you do NOTHING to the coarse
> solver.
>
>   Thanks,
>
>      Matt
>
>
>>    -eps_nev 1 -eps_ncv 10  -eps_monitor  -log_view > log_gmres 2>&1
>> makefile:59: recipe for target 'runkr_gmres' failed
>> make: *** [runkr_gmres] Error 91
>>
>> log-files is attached.
>>
>>
>> You mentioned that B is not symmetric. I assume it is elliptic
>>> (diffusion). Where does the asymmetry come from?
>>>
>>>
>> It is a two-group diffusion equations, where group denotes neutron enegry
>> discretisation.
>> Matrix B consists of neutron diffusion/leakage term, removal term and
>> minus neutron scatter source term between different energies, when matrix A
>> denotes neutron fission source.
>>
>> Diffusion term(Laplace operator) is elliptic and symmetric. Removal term
>> is diagonal only. However scatter term is asymmetry since scatter term from
>> high energy to low energy is far greater than the term from low to high.
>>
>>
>> Wenbo
>>
>>
>>> On Mon, Oct 2, 2017 at 9:39 AM, Wenbo Zhao <zhaowenbo.npic at gmail.com>
>>> wrote:
>>>
>>>> Matt,
>>>> Thanks for your reply.
>>>> For the defalt option doesnt work firstly( -st_ksp_type gmres
>>>> -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths 1), I tried
>>>> to test those options.
>>>>
>>>> Wenbo
>>>>
>>>> On Mon, Oct 2, 2017 at 9:08 PM, Matthew Knepley <knepley at gmail.com>
>>>> wrote:
>>>>
>>>>> On Mon, Oct 2, 2017 at 8:30 AM, Wenbo Zhao <zhaowenbo.npic at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Matt
>>>>>>
>>>>>> Because I am not clear about what will happen using 'preonly' for
>>>>>> large scale problem.
>>>>>>
>>>>>
>>>>> The size of the problem has nothing to do with 'preonly'. All it means
>>>>> is to apply a preconditioner without a Krylov solver.
>>>>>
>>>>>
>>>>>> It seems to use a direct solver from below,
>>>>>> http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/
>>>>>> KSP/KSPPREONLY.html
>>>>>>
>>>>>
>>>>> However, I still cannot understand why you would change the default?
>>>>>
>>>>>   Matt
>>>>>
>>>>>
>>>>>>
>>>>>> Thanks!
>>>>>> Wenbo
>>>>>>
>>>>>> On Mon, Oct 2, 2017 at 5:09 PM, Matthew Knepley <knepley at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> On Sun, Oct 1, 2017 at 9:53 PM, Wenbo Zhao <zhaowenbo.npic at gmail.com
>>>>>>> > wrote:
>>>>>>>
>>>>>>>> Matt,
>>>>>>>> Thanks for your reply.
>>>>>>>> It DOES make no sense for this problem.
>>>>>>>> But I am not clear about the 'preonly' option. Which solver is used
>>>>>>>> in preonly? I wonder if 'preonly' is suitable for large scale problem such
>>>>>>>> as 400,000,000 unknowns.
>>>>>>>> So I tried 'gmres' option and found these error messages.
>>>>>>>>
>>>>>>>
>>>>>>> I mean, why are you setting this at all. Just do not set the coarse
>>>>>>> solver. The default should work fine.
>>>>>>>
>>>>>>>   Thanks,
>>>>>>>
>>>>>>>     Matt
>>>>>>>
>>>>>>>
>>>>>>>> Could you give me some suggestions?
>>>>>>>>
>>>>>>>> Thanks.
>>>>>>>>
>>>>>>>> Wenbo
>>>>>>>>
>>>>>>>>
>>>>>>>> On Mon, Oct 2, 2017 at 12:34 AM, Matthew Knepley <knepley at gmail.com
>>>>>>>> > wrote:
>>>>>>>>
>>>>>>>>> On Sun, Oct 1, 2017 at 6:49 AM, Wenbo Zhao <
>>>>>>>>> zhaowenbo.npic at gmail.com> wrote:
>>>>>>>>>
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>> I met some questions when I use PETSC/SLEPC to solve two-group
>>>>>>>>>> neutron diffusion equations with finite difference method. The grid is
>>>>>>>>>> 3*3*3, when DOF on each points is 2. So the matrix size is 54*54.
>>>>>>>>>> It is generalized eigenvalue problem Ax=\lamda Bx, where B is
>>>>>>>>>> diagonally dominant matrix but not symmetry.
>>>>>>>>>> EPS is set as below,
>>>>>>>>>>  ierr = EPSSetProblemType(eps,EPS_GNHEP);CHKERRQ(ierr);¬
>>>>>>>>>>  ierr = EPSSetWhichEigenpairs(eps,EPS_
>>>>>>>>>> LARGEST_REAL);CHKERRQ(ierr);¬
>>>>>>>>>>
>>>>>>>>>> Krylovschur is used as eps sovler. GAMG is used as PC.
>>>>>>>>>> I tried agg_nsmooths and mg_coarse_ksp_type. Only non-smooths and
>>>>>>>>>> preonly is OK.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Why are you setting the coarse solver. This makes no sense.
>>>>>>>>>
>>>>>>>>>    Thanks,
>>>>>>>>>
>>>>>>>>>     Matt
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Test 1
>>>>>>>>>> $ make NCORE=1 runkr_nonsmooth
>>>>>>>>>> mpirun -n 1 ./step-41 \
>>>>>>>>>>    -st_ksp_type gmres  \
>>>>>>>>>>    -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths
>>>>>>>>>> 0 \
>>>>>>>>>>    -st_ksp_view  -mata AMAT.dat -matb BMAT.dat \
>>>>>>>>>>    -st_mg_coarse_ksp_type preonly   -st_mg_coarse_ksp_monitor  \
>>>>>>>>>>    -eps_nev 1 -eps_ncv 10  -eps_monitor  -log_view >
>>>>>>>>>> log_nonsmooth 2>&1
>>>>>>>>>>
>>>>>>>>>> Test 2
>>>>>>>>>> $ make NCORE=1 runkr_smooth
>>>>>>>>>> mpirun -n 1 ./step-41 \
>>>>>>>>>>    -st_ksp_type gmres  \
>>>>>>>>>>    -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths
>>>>>>>>>> 1 \
>>>>>>>>>>    -st_ksp_view  -mata AMAT.dat -matb BMAT.dat \
>>>>>>>>>>    -st_mg_coarse_ksp_type preonly   -st_mg_coarse_ksp_monitor  \
>>>>>>>>>>    -eps_nev 1 -eps_ncv 10  -eps_monitor -log_view > log_smooth
>>>>>>>>>> 2>&1
>>>>>>>>>> makefile:43: recipe for target 'runkr_smooth' failed
>>>>>>>>>> make: *** [runkr_smooth] Error 91
>>>>>>>>>>
>>>>>>>>>> Test 3
>>>>>>>>>> $ make NCORE=1 runkr_gmres
>>>>>>>>>> mpirun -n 1 ./step-41 \
>>>>>>>>>>    -st_ksp_type gmres  \
>>>>>>>>>>    -st_pc_type gamg -st_pc_gamg_type agg -st_pc_gamg_agg_nsmooths
>>>>>>>>>> 0 \
>>>>>>>>>>    -st_ksp_view  -mata AMAT.dat -matb BMAT.dat \
>>>>>>>>>>    -st_mg_coarse_ksp_type gmres  -st_mg_coarse_ksp_monitor
>>>>>>>>>> -st_mg_coarse_ksp_rtol 1.0e-6 \
>>>>>>>>>>    -eps_nev 1 -eps_ncv 10  -eps_monitor  -log_view > log_gmres
>>>>>>>>>> 2>&1
>>>>>>>>>> makefile:59: recipe for target 'runkr_gmres' failed
>>>>>>>>>> make: *** [runkr_gmres] Error 91
>>>>>>>>>>
>>>>>>>>>> Log files were attched.
>>>>>>>>>> The matrix file were also attched as AMAT.dat and BMAT.dat.
>>>>>>>>>>
>>>>>>>>>> Is it correct? Or something wrong with my code or commad-line?
>>>>>>>>>>
>>>>>>>>>> Thanks!
>>>>>>>>>>
>>>>>>>>>> Wenbo
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> 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.caam.rice.edu/%7Emk51/>
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> 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.caam.rice.edu/%7Emk51/>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> 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.caam.rice.edu/%7Emk51/>
>>>>>
>>>>
>>>>
>>>
>>
>
>
> --
> 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.caam.rice.edu/~mk51/>
>
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