Hello all the PETSc users and developers, I just started learning and exploring PETSc recently. I have a problem for the example: .../src/ksp/ksp/examples/ex2f.f I run several times with different numbers of processors. Here are the results.
nan_jia at mir:/thayerfs/research/anatoly/NAN/Petsc/petsc-3.1-p8/src/ksp/ksp/examples/tutorials$ mpiexec -np 1 ./ex2f -m 100 -n 100 Norm of error 0.8936E-02 iterations 65 nan_jia at mir:/thayerfs/research/anatoly/NAN/Petsc/petsc-3.1-p8/src/ksp/ksp/examples/tutorials$ mpiexec -np 2 ./ex2f -m 100 -n 100 Norm of error 0.3148E-01 iterations 89 nan_jia at mir:/thayerfs/research/anatoly/NAN/Petsc/petsc-3.1-p8/src/ksp/ksp/examples/tutorials$ mpiexec -np 3 ./ex2f -m 100 -n 100 Norm of error 0.3193E-01 iterations 92 What is weird to me is that with more processors, the norm does not decrease but increases, do does the number of iterations. I also try to compare .../src/ksp/ksp/examples/ex2f.f with .../src/ksp/ksp/examples/ex1f.f to see the difference between the sequential and parallel code in order to understand how PETSc parallelizes the code. This is my first use the PETSc mailing list. Thanks everyone. Best, Nan
