### Convergence problem

Posted:

**Tue Jul 24, 2012 1:57 am**I'm trying to evaluate CULA Sparse solver efficiency compared to CPU PETSC library.

The input linear system (complex) that must be solved is assembed by PETSC library. I've passed the matrix and the right-hand side terms to CULA solver using a COO format. I've tried to resolve the system using Bicg solver plus ILU0 preconditioner (the same that I've used inside my PETSC program) but I always obtain "Maximum iterations reached without convergence". I've tried different combination of solver and preconditioner without obtaining convergence. The same system can be resolved in PETSC in 56 iterations. How can be justified this behavior?

Thanks

The input linear system (complex) that must be solved is assembed by PETSC library. I've passed the matrix and the right-hand side terms to CULA solver using a COO format. I've tried to resolve the system using Bicg solver plus ILU0 preconditioner (the same that I've used inside my PETSC program) but I always obtain "Maximum iterations reached without convergence". I've tried different combination of solver and preconditioner without obtaining convergence. The same system can be resolved in PETSC in 56 iterations. How can be justified this behavior?

Thanks