[petsc-users] Using superlu_dist in a direct solve

[Sanjay Govindjee]

I decided to go with ksp/ksp/exampeles/tutorials/ex2.c; I was unsure how 
to convert the run lines for snes/examples/ex5.c to work with a direct 
solver as I am not versed in SNES options.

Notwithstanding something strange is happening only on select examples.  
With ksp/ksp/exampeles/tutorials/ex2.c and the run line:

-@${MPIEXEC} -n 2 ./ex2 -ksp_monitor_short -m 20 -n 20 -ksp_type preonly 
-pc_type lu -pc_factor_mat_solver_package superlu_dist

I get good results (of the order):

Norm of error 1.85464e-14 iterations 1

using both superlu_dist and spooles.

My BLAS/LAPACK: -llapack -lblas (so native to my machine).

If you can guide me on a run line for the snes ex5.c I can try that 
too.  I'll also try to construct a GCC build later to see if that is an 
issue.

-sanjay


On 12/23/12 5:58 PM, Matthew Knepley wrote:
> On Sun, Dec 23, 2012 at 8:08 PM, Sanjay Govindjee <s_g at berkeley.edu 
> <mailto:s_g at berkeley.edu>> wrote:
>
>     Not sure what you mean by where is your matrix?  I am simply
>     running ex6 in the ksp/examples/tests directory.
>
>     The reason I ran this test is because I was seeing the same
>     behavior with my finite element code (on perfectly benign problems).
>
>     Is there a built-in test that you use to check that superlu_dist
>     is working properly with petsc?
>     i.e. something you know that works with with petsc 3.3-p5?
>
>
> 1) Run it on a SNES ex5 (or KSP ex2), which is a nice Laplacian
>
> 2) Compare with MUMPS
>
>    Matt
>
>     -sanjay
>
>
>
>     On 12/23/12 4:56 PM, Jed Brown wrote:
>>     Where is your matrix? It might be ending up with a very bad
>>     pivot. If the problem can be reproduced, it should be reported to
>>     the SuperLU_DIST developers to fix. (Note that we do not see this
>>     with other matrices.) You can also try MUMPS.
>>
>>
>>     On Sun, Dec 23, 2012 at 6:48 PM, Sanjay Govindjee
>>     <s_g at berkeley.edu <mailto:s_g at berkeley.edu>> wrote:
>>
>>         I wanted to use SuperLU Dist to perform a direct solve but
>>         seem to be encountering
>>         a problem.  I was wonder if this is a know issue and if there
>>         is a solution for it.
>>
>>         The problem is easily observed using ex6.c in
>>         src/ksp/ksp/examples/tests.
>>
>>         Out of the box: make runex6 produces a residual error of
>>         O(1e-11), all is well.
>>
>>         I then changed the run to run on two processors and add the flag
>>         -pc_factor_mat_solver_package spooles this produces a
>>         residual error of O(1e-11), all is still well.
>>
>>         I then switch over to -pc_factor_mat_solver_package
>>         superlu_dist and the
>>         residual error comes back as 22.6637! Something seems very wrong.
>>
>>         My build is perfectly vanilla:
>>
>>         export PETSC_DIR=/Users/sg/petsc-3.3-p5/
>>         export PETSC_ARCH=intel
>>
>>         ./configure --with-cc=icc --with-fc=ifort \
>>         -download-{spooles,parmetis,superlu_dist,prometheus,mpich,ml,hypre,metis}
>>
>>         make PETSC_DIR=/Users/sg/petsc-3.3-p5/ PETSC_ARCH=intel all
>>         make PETSC_DIR=/Users/sg/petsc-3.3-p5/ PETSC_ARCH=intel test
>>
>>         -sanjay
>>
>>
>
>     -- 
>     -----------------------------------------------
>     Sanjay Govindjee, PhD, PE
>     Professor of Civil Engineering
>     Vice Chair for Academic Affairs
>
>     779 Davis Hall
>     Structural Engineering, Mechanics and Materials
>     Department of Civil Engineering
>     University of California
>     Berkeley, CA 94720-1710
>
>     Voice:+1 510 642 6060  <tel:%2B1%20510%20642%206060>
>     FAX:+1 510 643 5264  <tel:%2B1%20510%20643%205264>
>     s_g at berkeley.edu  <mailto:s_g at berkeley.edu>
>     http://www.ce.berkeley.edu/~sanjay  <http://www.ce.berkeley.edu/%7Esanjay>
>     -----------------------------------------------
>
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>
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> -- 
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> experiments is infinitely more interesting than any results to which 
> their experiments lead.
> -- Norbert Wiener

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