[petsc-users] superlu_dist and MatSolveTranspose

Antoine De Blois antoine.deblois at aero.bombardier.com
Mon Sep 22 12:11:59 CDT 2014


Dear all,

Sorry for the delay on this topic. 

Thank you Gaetan for your suggestion. I had thought about doing that originally, but I had left it out since I thought that a rank owned the entire row of the matrix (and not only the sub-diagonal part). I will certainly give it a try. 

I still need the MatSolveTranspose since I need the ability to reuse the residual jacobian matrix from the flow (a 1st order approximation of it), which is assembled in a non-transposed format. This way the adjoint system is solved in a pseudo-time step manner, where the product of the exact jacobian matrix and the adjoint vector is used as a source term in the rhs.

Hong, do you have an estimation of the time required to implement it in superlu_dist?

Best,
Antoine

-----Message d'origine-----
De : Hong [mailto:hzhang at mcs.anl.gov] 
Envoyé : Friday, August 29, 2014 9:14 PM
À : Gaetan Kenway
Cc : Antoine De Blois; petsc-users at mcs.anl.gov
Objet : Re: [petsc-users] superlu_dist and MatSolveTranspose

We can add MatSolveTranspose() to the petsc interface with superlu_dist.

Jed,
Are you working on it? If not, I can work on it.

Hong

On Fri, Aug 29, 2014 at 6:14 PM, Gaetan Kenway <gaetank at gmail.com> wrote:
> Hi Antoine
>
> We are also using PETSc for solving adjoint systems resulting from 
> CFD. To get around the matSolveTranspose issue we just assemble the 
> transpose matrix directly and then call KSPSolve(). If this is 
> possible in your application I think it is probably the best approach
>
> Gaetan
>
>
> On Fri, Aug 29, 2014 at 3:58 PM, Antoine De Blois 
> <antoine.deblois at aero.bombardier.com> wrote:
>>
>> Hello Jed,
>>
>> Thank you for your quick response. So I spent some time to dig deeper 
>> into my problem. I coded a shell script that passes through a bunch 
>> of ksp_type, pc_type and sub_pc_type. So please disregard the comment 
>> about the "does not converge properly for transpose". I had taken 
>> that conclusion from my own code (and not from the ex10 and extracted 
>> matrix), and a KSPSetFromOptions was missing. Apologies for that.
>>
>> What remains is the performance issue. The MatSolveTranspose takes a 
>> very long time to converge. For a matrix of 3 million rows, 
>> MatSolveTranspose takes roughly 5 minutes on 64 cpus, whereas the 
>> MatSolve is almost instantaneous!. When I gdb my code, petsc seems to 
>> be stalled in the MatLUFactorNumeric_SeqAIJ_Inode () for a long time. 
>> I also did a top on the compute node to check the RAM usage. It was 
>> hovering over 2 gig, so memory usage does not seem to be an issue here.
>>
>> #0  0x00002afe8dfebd08 in MatLUFactorNumeric_SeqAIJ_Inode ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #1  0x00002afe8e07f15c in MatLUFactorNumeric ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #2  0x00002afe8e2afa99 in PCSetUp_ILU ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #3  0x00002afe8e337c0d in PCSetUp ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #4  0x00002afe8e39d643 in KSPSetUp ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #5  0x00002afe8e39e3ee in KSPSolveTranspose ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #6  0x00002afe8e300f8c in PCApplyTranspose_ASM ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #7  0x00002afe8e338c13 in PCApplyTranspose ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #8  0x00002afe8e3a8a84 in KSPInitialResidual ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #9  0x00002afe8e376c32 in KSPSolve_GMRES ()
>>    from
>> /gpfs/fs2/aero/SOFTWARE/FLOW_SOLVERS/FANSC/EXT_LIB/petsc-3.5.1/lib/li
>> bpetsc.so.3.5
>> #10 0x00002afe8e39e425 in KSPSolveTranspose ()
>>
>> For that particular application, I was using:
>> ksp_type:                       gmres
>> pc_type:                        asm
>> sub_pc_type:                    ilu
>> adj_sub_pc_factor_levels        1
>>
>> For small matrices, the MatSolveTranspose computing time is very 
>> similar to the simple MatSolve.
>>
>> And if I want to revert to a MatTranspose followed by the MatSolve, 
>> then the MatTranspose takes forever to finish... For a matrix of 3 
>> million rows, MatTranspose takes 30 minutes on 64 cpus!!
>>
>> So thank you for implementing the transpose solve in superlu_dist. It 
>> would also be nice to have it with hypre.
>> Let me know what you think and ideas on how to improve my 
>> computational time, Regards, Antoine
>>
>> -----Message d'origine-----
>> De : Jed Brown [mailto:jed at jedbrown.org] Envoyé : Thursday, August 
>> 28, 2014 5:01 PM À : Antoine De Blois; 'petsc-users at mcs.anl.gov'
>> Objet : Re: [petsc-users] superlu_dist and MatSolveTranspose
>>
>> Antoine De Blois <antoine.deblois at aero.bombardier.com> writes:
>>
>> > Hello everyone,
>> >
>> > I am trying to solve a A^T x = b system. For my applications, I had 
>> > realized that the MatSolveTranspose does not converge properly.
>>
>> What do you mean "does not converge properly"?  Can you send a test 
>> case where the transpose solve should be equivalent, but is not?  We 
>> have only a few tests for transpose solve and not all preconditioners 
>> support it, but where it is supported, we want to ensure that it is correct.
>>
>> > Therefore, I had implemented a MatTranspose followed by a MatSolve.
>> > This proved to converge perfectly (which is strange since the 
>> > transposed matrix has the same eigenvalues as the untransposed...).
>> > The problem is that for bigger matrices, the MatTranspose is very 
>> > costly and thus cannot be used.
>>
>> Costly in terms of memory?  (I want you to be able to use 
>> KSPSolveTranspose, but I'm curious what you're experiencing.)
>>
>> > I tried using the superlu_dist package. Although it the package 
>> > works perfectly for the MatSolve, I get the an "No support for this 
>> > operation for this object type" error  with MatSolveTransopse. I 
>> > reproduced the error using the MatView an ex10 tutorial. I can 
>> > provide the matrix and rhs upon request. My command line was:
>> >
>> > ex10 -f0 A_and_rhs.bin -pc_type lu -pc_factor_mat_solver_package 
>> > superlu_dist -trans
>> >
>> > So it there an additional parameter I need to use for the 
>> > transposed solve?
>> >
>> > [0]PETSC ERROR: --------------------- Error Message
>> > --------------------------------------------------------------
>> > [0]PETSC ERROR: No support for this operation for this object type 
>> > [0]PETSC ERROR: Matrix type mpiaij
>>
>> This is easy to add.  I'll do it now.
>>
>> > [0]PETSC ERROR: See 
>> > http://www.mcs.anl.gov/petsc/documentation/faq.html
>> > for trouble shooting.
>> > [0]PETSC ERROR: Petsc Release Version 3.5.1, unknown [0]PETSC ERROR:
>> > /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/example
>> > s/t
>> > utorials/ex10 on a ARGUS_impi_opt named hpc-user11 by ad007804 Thu 
>> > Aug
>> > 28 16:41:15 2014 [0]PETSC ERROR: Configure options --CFLAGS="-xHost 
>> > -axAVX" --download-hypre --download-metis --download-ml 
>> > --download-parmetis --download-scalapack --download-superlu_dist 
>> > --download-mumps --with-c2html=0 --with-cc=mpiicc 
>> > --with-fc=mpiifort --with-cxx=mpiicpc --with-debugging=yes
>> > --prefix=/gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/petsc-3.5.
>> > 1 
>> > --with-cmake=/gpfs/fs1/aero/SOFTWARE/TOOLS/CMAKE/cmake-2.8.7/bin/cm
>> > ake
>> > --with-valgrind=/gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/valgrind-
>> > 3.9 .0/bin/valgrind --with-shared-libraries=0 [0]PETSC ERROR: #1
>> > MatSolveTranspose() line 3473 in
>> > /gpfs/fs2/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/mat/interface/m
>> > atr ix.c [0]PETSC ERROR: #2 PCApplyTranspose_LU() line 214 in 
>> > /gpfs/fs2/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/pc/impls/fa
>> > cto r/lu/lu.c [0]PETSC ERROR: #3 PCApplyTranspose() line 573 in 
>> > /gpfs/fs2/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/pc/interfac
>> > e/p recon.c [0]PETSC ERROR: #4 KSP_PCApply() line 233 in 
>> > /gpfs/fs2/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/include/petsc-priva
>> > te/ kspimpl.h [0]PETSC ERROR: #5 KSPInitialResidual() line 63 in 
>> > /gpfs/fs2/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/interfa
>> > ce/ itres.c [0]PETSC ERROR: #6 KSPSolve_GMRES() line 234 in 
>> > /gpfs/fs2/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/impls/g
>> > mre s/gmres.c [0]PETSC ERROR: #7 KSPSolveTranspose() line 704 in 
>> > /gpfs/fs2/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/interfa
>> > ce/ itfunc.c [0]PETSC ERROR: #8 main() line 324 in 
>> > /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/example
>> > s/t
>> > utorials/ex10.c
>> >
>> > FYI, the transpose solve is a typical application for adjoint 
>> > optimization. There should be a big adjoint community of developers 
>> > that try to solve the transposed matrix.
>> >
>> > Any help is much appreciated,
>> > Best,
>> > Antoine
>> >
>> >
>> > Antoine DeBlois
>> > Specialiste ingenierie, MDO lead / Engineering Specialist, MDO lead 
>> > Aéronautique / Aerospace 514-855-5001, x 50862 
>> > antoine.deblois at aero.bombardier.com<mailto:antoine.deblois at aero.bom
>> > bar
>> > dier.com>
>> >
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