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 [email protected]<mailto:[email protected]> 2351 Blvd Alfred-Nobel Montreal, Qc H4S 1A9 [Description : Description : http://signatures.ca.aero.bombardier.net/eom_logo_164x39_fr.jpg] CONFIDENTIALITY NOTICE - This communication may contain privileged or confidential information. If you are not the intended recipient or received this communication by error, please notify the sender and delete the message without copying
