Hello, I am trying to test PETSc capability of solving sparse linear systems in parallel with GPU.
I compiled and tried to run example src/ksp/ksp/examples/tutorials/ex2.c, which can be executed in parallel. In this example matrix and vectors created using VecSetFromOptions() and MatSetFromOptions(). According to the page http://www.mcs.anl.gov/petsc/petsc-2/features/gpus.html , I execute the program with keys -vec_type mpicusp -mat_type mpiaijcusp in parallel on the different number of GPUs. Full command: cleo-submit -np 1 ex2 -ksp_type cg -vec_type mpicusp -mat_type mpiaijcusp -m 800 -n 800 Where 'cleo-submit' is a batch manager utility. I tested the program on 1, 2 and 3 GPUs. As a result I have output as (for 3 GPUs): Norm of error 0.00012322 iterations 448 Norm of error 0.00012322 iterations 448 Norm of error 0.00012322 iterations 448 and run times: 30, 40 and 46 seconds respectively. What can be a cause of these results? -- Best regards, Eugene
