Federico : > > Coarse grid solver -- level ------------------------------- > KSP Object: (mg_levels_0_) 128 MPI processes > type: chebyshev > Chebyshev: eigenvalue estimates: min = 0.223549, max = 2.45903 > Chebyshev: eigenvalues estimated using gmres with translations > [0. 0.1; 0. 1.1] > KSP Object: (mg_levels_0_esteig_) 128 MPI processes > type: gmres > GMRES: restart=30, using Classical (unmodified) Gram-Schmidt > Orthogonalization with no iterative refinement > GMRES: happy breakdown tolerance 1e-30 > maximum iterations=10, initial guess is zero > *tolerances: relative=1e-12*, absolute=1e-50, divergence=10000. > left preconditioning > *using PRECONDITIONED norm type for convergence test* > maximum iterations=2, initial guess is zero > tolerances: relative=1e-05, absolute=1e-50, divergence=10000. > left preconditioning > using NONE norm type for convergence test >
Chebyshev requires an estimate of operator eigenvalues, for which we use few gmres iterations. These default options are used for eigenvalue estimates. Hong