[petsc-users] mumps solve with same nonzero pattern(Hong Zhang)

[Hong Zhang]

Wen :

> Reply to
>
>> This is weird.  Try
>> 1) increase work  space with
>> -mat_mumps_icntl_14 50 (default is 20)
>> 2) different matrix orderings with
>> -mat_mumps_icntl_7 2 (or number from 0 to 6)
>>
>> Run your code with '-log_summary' and see which routine causes this huge
>> difference.
>>
> Why your '-log_summary' only gives
KSPSolve               4 1.0 2.2645e+03 1.0 0.00e+00 0.0 3.9e+04 3.6e+02
5.4e+01 96  0 27  0  9  96  0 27  0  9     0
PCSetUp                4 1.0 2.2633e+03 1.0 0.00e+00 0.0 0.0e+00 0.0e+00
3.4e+01 96  0  0  0  6  96  0  0  0  6     0
PCApply                4 1.0 1.1641e+00 1.0 0.00e+00 0.0 3.9e+04 3.6e+02
2.0e+01  0  0 27  0  3   0  0 27  0  3     0

I get
petsc-dev/src/ksp/ksp/examples/tutorials>mpiexec -n 2 ./ex2 -pc_type lu
-pc_factor_mat_solver_package mumps -log_summary
MatMult                2 1.0 1.6904e-04 1.0 4.44e+02 1.0 4.0e+00 5.6e+01
0.0e+00  0 47 25 13  0   0 47 33 13  0     5
MatSolve               2 1.0 3.8259e-03 1.0 0.00e+00 0.0 8.0e+00 1.9e+02
6.0e+00 10  0 50 84  7  11  0 67 87  9     0
MatLUFactorSym         1 1.0 2.9058e-03 1.0 0.00e+00 0.0 0.0e+00 0.0e+00
8.0e+00  7  0  0  0  9   8  0  0  0 11     0
MatLUFactorNum         1 1.0 2.0120e-03 1.0 0.00e+00 0.0 0.0e+00 0.0e+00
2.0e+00  5  0  0  0  2   6  0  0  0  3     0
...

I like to check these functions. In addition, have you tried other matrix
orderings?
Hong

>
>> Hong
>>
>>
> I just tested the problem according to what you suggested. I set icntl_14
> = 50 and icntl_7 = 5 (METIS). The problem still persisted. The first solve
> took 920 second and second solve took 215 second with same nonzero pattern
> pc set up. I also attached the log_summary output file. Do you have any
> further suggestion?  Thanks.
>
> Regards,
> Wen
>
>
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