[petsc-users] MUMPS error and superLU error

[venkatesh g]

On Tue, May 26, 2015 at 9:02 PM, Hong <hzhang at mcs.anl.gov> wrote:

> 'A serial job in MATLAB for the same matrices takes < 60GB. '
> Can you run this case in serial? If so, try petsc, superlu or mumps to
> make sure the matrix is non-singular.
>
B matrix is singular but I get my result in Petsc and Mumps for small
matrices.

>
> Both mumps and superlu_dist show crash in MatFactorNumeric(). Mumps gives
> error
> [16]PETSC ERROR: Error reported by MUMPS in numerical factorization phase:
> Cannot allocate required memory 65710 megabytes.
>
> Does your code work for smaller problems?
>
Yes code works for small problems

> Try using more processors?
>
> Why use such huge '-mat_mumps_icntl_14 200000' (percentage of estimated
> workspace increase)? The default is 20. Try 40?
>
> Superlu_dist usually uses less memory than mumps, but it also crashes. I
> guess something wrong with your matrix. Is it singular?
>
The B matrix is singular. So Super Lu cant be used is it ?


> Run superlu_dist on a slightly smaller matrix with option
> '-mat_superlu_dist_statprint' which displays memory usage info., e.g.,
>
Ok I will do that and check.

> petsc/src/ksp/ksp/examples/tutorials (maint)
> $ mpiexec -n 2 ./ex2 -pc_type lu -pc_factor_mat_solver_package
> superlu_dist -mat_superlu_dist_statprint
> Nonzeros in L       560
> Nonzeros in U       560
> nonzeros in L+U     1064
> nonzeros in LSUB    248
> NUMfact space (MB) sum(procs):  L\U 0.01 all 0.05
> Total highmark (MB):  All 0.05 Avg 0.02 Max 0.02
> EQUIL time             0.00
> ROWPERM time           0.00
> COLPERM time           0.00
> SYMBFACT time          0.00
> DISTRIBUTE time        0.00
> FACTOR time            0.00
> Factor flops 1.181000e+04 Mflops     4.80
> SOLVE time             0.00
> SOLVE time             0.00
> Solve flops 2.194000e+03 Mflops     4.43
> SOLVE time             0.00
> Solve flops 2.194000e+03 Mflops     5.14
> Norm of error 1.18018e-15 iterations 1
>
> Hong
>
>
> On Tue, May 26, 2015 at 9:03 AM, venkatesh g <venkateshgk.j at gmail.com>
> wrote:
>
>> I posted a while ago in MUMPS forums but no one seems to reply.
>>
>> I am solving a large generalized Eigenvalue problem.
>>
>> I am getting the following error which is attached, after giving the
>> command:
>>
>> /cluster/share/venkatesh/petsc-3.5.3/linux-gnu/bin/mpiexec -np 64 -hosts
>> compute-0-4,compute-0-6,compute-0-7,compute-0-8 ./ex7 -f1 a72t -f2 b72t
>> -st_type sinvert -eps_nev 3 -eps_target 0.5 -st_ksp_type preonly
>> -st_pc_type lu -st_pc_factor_mat_solver_package mumps -mat_mumps_icntl_14
>> 200000
>>
>> IT IS impossible to allocate so much memory per processor.. it is asking
>> like around 70 GB per processor.
>>
>> A serial job in MATLAB for the same matrices takes < 60GB.
>>
>> After trying out superLU_dist, I have attached the error there also
>> (segmentation error).
>>
>> Kindly help me.
>>
>> Venkatesh
>>
>>
>>
>
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