[petsc-users] PCASM in transposed format

[Barry Smith]

   Please email the data file to petsc-maint at mcs.anl.gov  or if you fear it is too large tell us from where we may download it.

  Barry

On Sep 22, 2014, at 1:28 PM, Antoine De Blois <antoine.deblois at aero.bombardier.com> wrote:

> Dear all,
>  
> I am using the ASM preconditioner to solve a transposed system through MatSolveTranspose. Strangely, the results I obtain differ in each call. Is there a non-deterministic operations within ASM? If I use it in a non-transposed way, I get correct results… If I use GASM, then the results are always the same, both in transposed and non-transposed formats.
>  
> Below is a log of my calls (note that some of them actually diverged).
> I can give you my matrix and rhs if you want.
>  
> Regards,
> Antoine
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type asm              
> Number of iterations = 690
> Residual norm 0.000617544
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type asm
> Number of iterations = 475
> Residual norm 0.000727253
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type asm
> Number of iterations = 10000
> Residual norm 1.3866
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type asm
> Number of iterations = 568
> Residual norm 0.000684401
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type asm
> Number of iterations = 540
> Residual norm 0.000555548
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type asm
> Number of iterations = 10000
> Residual norm 1.30198
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type asm
> Number of iterations = 207
> Residual norm 0.000555849
>  
>  
> ---------------
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type gasm
> Number of iterations = 297
> Residual norm 0.000600143
>  
> $ mpirun -np 4 /gpfs/fs1/aero/SOFTWARE/TOOLS/PROGRAMMING/petsc/src/ksp/ksp/examples/tutorials/ex10 -f0 A_and_rhs.bin  -trans -pc_type gasm
> Number of iterations = 297
> Residual norm 0.000600143
>  
>  
>  
> Antoine DeBlois
> Specialiste ingenierie, MDO lead / Engineering Specialist, MDO lead
> Aéronautique / Aerospace
> 514-855-5001, x 50862
> antoine.deblois at aero.bombardier.com
> 
> 2351 Blvd Alfred-Nobel
> Montreal, Qc
> H4S 1A9
> 
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