From: John Peterson <jwpeterson@gm...>  20120129 21:27:57

On Sun, Jan 29, 2012 at 12:47 PM, Bao Kai <paeanball@...> wrote: > Hi, > > I am just starting to lean Libmesh. > > I have a question on ex13. I want to know what the Newton term means in ex13. > theta*dt*(U*grad_u)*phi[i][qp]); // Newton term The Newton method of Example 13 is atypical: rather than solving for the "update" du_{k+1} = u_{k+1}  u_{k}, it solves for u_{k+1} directly. So the "standard" Newton iteration: J_{k} du_{k+1} = F_{k} is instead written as: J_{k} u_{k+1} = F_{k} + J_{k} u_{k} This modified RHS can be computed by hand; it involves the term you asked about above.  John 