"Sun, Hui" <[email protected]> writes: > 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?
NonlinearGS is primarily used as a smoother in nonlinear multigrid (FAS). It is not used by the default configuration. > 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? ./ex19 -help | grep -A5 ksp_type this will output a list of available KSPs.
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