GMRES method .vs. bcg stab
 

Dear friends:

I want to know , GMRES and BI_CG_STAB, which is more better. regards

Re: GMRES method .vs. bcg stab
 

It depends on your equations, discretization, and preconditioner. You should try both (maybe (TF)QMR as well) with a selection of preconditioners. For most combinations from the following table, there is a matrix for which that combination is significantly better than the others. GMRES is pretty robust and makes a good default.

http://www-unix.mcs.anl.gov/petsc/pe...lvertable.html