From: Roy Stogner <roystgnr@ic...>  20070829 16:48:49

On Wed, 29 Aug 2007, Yujie wrote: > I want to know whether I may generate multiple system matrixes and obtain > multiple solutions? Yes. Each subclass of System has its own solution vector; each subclass of ImplicitSystem has its own matrix. If you want to add additional matrices the same system, use System::add_matrix() as in example 7. If you want to solve for different variables with independent matrices, use EquationSystems::add_system() to add multiple systems. > In addition, if the problem to be solved includes several PDEs (they > are coupled), whether is libmesh avalible? If it ok, how to deal > with them? Yes. If you want the coupling to be strong, you add additional variables to the same System object; if you want the coupling to be weak you add additional systems to the same EquationSystems object. For example if you're solving an incompressible flow and transport problem, you might have one system with velocity components u,v,w and pressure p, and a second system with concentration c.  Roy 