[petsc-users] SuperLU convergence problem

[Danyang Su]

Hi Hong,

I just checked using ex10 for these matrices and rhs, they all work 
fine. I found something is wrong in my code when using direct solver.  
The second parameter mat in PCFactorGetMatrix(PC pc,Mat *mat) is not 
initialized in my code for SUPERLU or MUMPS.

I will fix this bug, rerun the tests and get back to you later.

Thanks very much,

Danyang

On 15-12-03 01:59 PM, Hong wrote:
> Danyang :
> Further testing a_flow_check_168.bin,
> ./ex10 -f0 
> /Users/Hong/Downloads/matrix_and_rhs_bin/a_flow_check_168.bin -rhs 
> /Users/Hong/Downloads/matrix_and_rhs_bin/x_flow_check_168.bin -pc_type 
> lu -pc_factor_mat_solver_package superlu -ksp_monitor_true_residual 
> -mat_superlu_conditionnumber
>   Recip. condition number = 1.610480e-12
>   0 KSP preconditioned resid norm 6.873340313547e+09 true resid norm 
> 7.295020990196e+03 ||r(i)||/||b|| 1.000000000000e+00
>   1 KSP preconditioned resid norm 2.051833296449e-02 true resid norm 
> 2.976859070118e-02 ||r(i)||/||b|| 4.080672384793e-06
> Number of iterations =   1
> Residual norm 0.0297686
>
> condition number of this matrix = 1/1.610480e-12 = 1.e+12,
> i.e., this matrix is ill-conditioned.
>
> Hong
>
>
>     Hi Hong,
>
>     The binary format of matrix, rhs and solution can be downloaded
>     via the link below.
>
>     https://www.dropbox.com/s/cl3gfi0s0kjlktf/matrix_and_rhs_bin.tar.gz?dl=0
>
>     Thanks,
>
>     Danyang
>
>
>     On 15-12-03 10:50 AM, Hong wrote:
>>     Danyang:
>>
>>
>>
>>         To my surprising, solutions from SuperLU at timestep 29 seems
>>         not correct for the first 4 Newton iterations, but the
>>         solutions from iteration solver and MUMPS are correct.
>>
>>         Please find all the matrices, rhs and solutions at timestep
>>         29 via the link below. The data is a bit large so that I just
>>         share it through Dropbox. A piece of matlab code to read
>>         these data and then computer the norm has also been attached.
>>         _https://www.dropbox.com/s/rr8ueysgflmxs7h/results-check.tar.gz?dl=0_
>>
>>
>>     Can you send us matrix in petsc binary format?
>>
>>     e.g., call MatView(M, PETSC_VIEWER_BINARY_(PETSC_COMM_WORLD))
>>     or '-ksp_view_mat binary'
>>
>>     Hong
>>
>>
>>
>>         Below is a summary of the norm from the three solvers at
>>         timestep 29, newton iteration 1 to 5.
>>
>>         Timestep 29
>>         Norm of residual seq 1.661321e-09, superlu 1.657103e+04,
>>         mumps 3.731225e-11
>>         Norm of residual seq 1.753079e-09, superlu 6.675467e+02,
>>         mumps 1.509919e-13
>>         Norm of residual seq 4.914971e-10, superlu 1.236362e-01,
>>         mumps 2.139303e-17
>>         Norm of residual seq 3.532769e-10, superlu 1.304670e-04,
>>         mumps 5.387000e-20
>>         Norm of residual seq 3.885629e-10, superlu 2.754876e-07,
>>         mumps 4.108675e-21
>>
>>         Would anybody please check if SuperLU can solve these
>>         matrices? Another possibility is that something is wrong in
>>         my own code. But so far, I cannot find any problem in my code
>>         since the same code works fine if I using iterative solver or
>>         direct solver MUMPS. But for other cases I have tested,  all
>>         these solvers work fine.
>>
>>         Please let me know if I did not write down the problem clearly.
>>
>>         Thanks,
>>
>>         Danyang
>>
>>
>>
>>
>
>

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