[petsc-users] help with snes

[Kontsantinos Kontzialis]

Dear all,

I use snes to apply an implicit Runge-Kutta method. I see that the snes 
and ksp solvers converge very slowly. Here is the runtime options I use:

mpiexec -np 4 ./hoac cylinder -snes_mf_operator -pc_type hypre 
-pc_hypre_type euclid -pc_hypre_euclid_levels 2 -ksp_type gmres -dt 
1.0e-1 -n_out 10 -file_out cylinder.txt -mat_inode_limit 5 -snes_monitor 
-end_time 1.0e+1 -roe_flux -snes_converged_reason -snes_max_fail 50 
-u_mom 0.2 -implicit -implicit_type 2 -snes_atol 1.0e-6 
-snes_ksp_ew_conv -ksp_gmres_cgs_refinement_type REFINE_IFNEEDED 
-ksp_gmres_classicalgramschmidt

Also, I use coloring to compute the jacobian of the system. Any suggestions?

Thank you,

Costas