[petsc-users] questions on KSP solver and preconditioning

[Sun, Hui]

Hello, I'm reading ex19.c from examples under directory snes. The version I'm using is 3.3. In the code, a user defined function NonlinearGS is implemented, and is registered thru the command
ierr = SNESSetGS(snes, NonlinearGS, (void*)&user);CHKERRQ(ierr);

I'm wondering if this only serves as a preconditioner? Because I read from the output that the default ksp solver is gmres. I'm also wondering what shall I do if I want to make the user defined NonlinearGS the actual solver instead of the preconditioner?

>From the discussion a few days ago, I knew that by specifying option -ksp_type gmres or -ksp_type bcgs, you use gmres or bcgs as your solvers, where then can I find a database for the ksp solvers?

Best,
Hui
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20140605/ebcbdf14/attachment.html>