[Trilinos-Users] GMRES faster than CG

[Rony Speck]

Hello everybody

When using AztecOO, I noticed that GMRES converges faster and needs less time than CG when using IFPACK IC or ML as a preconditioner. 
The difference is quite large. The system is spd. When using no preconditioner, CG needs less iterations and is faster.
I also plotted the iteration numbers against the norms of the residuals. For GMRES the curve is smooth, whereas for
CG the curve is rather erratic. For both solvers I set the convergence criterium to AZ_rhs. 

Has anyone else experienced this?

Thanks for your answers
Rony Speck


_________________________________________________________________
Sie haben nie Platz in Ihrer Inbox? Mit Windows Live Hotmail haben Sie jetzt 5GB Speicherplatz - gratis! Holen Sie sich hier Ihren neuen  Windows Live Hotmail Account!
http://get.live.com/mail/overview