Thank you.
I will ask to update to 3.4 but I am working on a supercomputer thus I
do not have control on the installed software.
So you suggest to use conjugate gradient + multigrid as preconditioner,
correct?
If so, I retain
-ksp_type cg
instead of
-ksp_type richardson
correct?
Michele
On 05/17/2013 12:45 PM, Jed Brown wrote:
Michele Rosso <[email protected]> writes:
Hi,
I am successfully using PETSc (v3.3) in parallel to solve the Poisson
equation in 3D .
Please upgrade to petsc-3.4 when you get a chance.
The discretization is done by using finite difference on a uniform
structured grid. So far I used the conjugate gradient method, but I
would like to give a try to multigrid. The documentation describes
multigrid as a preconditioner only, thus I would like to know if it is
possible to use multigrid as a solver
-ksp_type richardson
will not accelerate your multigrid. Krylov with preconditioning is
almost never slower, and a lot more robust.
and, if so, if you could give my some tips to start.
-pc_type mg -pc_mg_levels 3
-pc_type gamg
-pc_type ml
-pc_type hypre
