Re: [Getfem-users] Solving a PDE with no boundary conditions in getfem++

[Yves RENARD]

Dear Ali,

It is simply not possible to solve a partial differential equation without
boundary conditions. In the weak formulation, if you do not add any  
term so you have implicitely a homogeneous Neumann condition. This is  
the case if you do not add any boundary condition brick. But in that  
case, the solution will be defined modulo an additive constant (or  
modulo a rigid motion). This make the stiffness matrix having a  
certain number of vanishing eigenvalues.

Best regards,

Yves.

Quoting Ali - <address@hidden>:

> Yves,
>
> I have sent this question to getfem mailing list, but it has not   
> appeared there (yet, after a few hours), a quick reply on this is   
> appreciated.
>
>
> -Ali
>
> From: address@hidden
> To: address@hidden
> Subject: Solving a PDE with no boundary conditions
> Date: Mon, 23 Jun 2008 17:34:11 +0100
>
>
>
>
>
>
>
> Hi,
>
> How is it possible in getfem++ to solve a PDE with no boundary   
> conditions at all? In the case specifying a boundary condition is   
> mandatory, how can we pass a dummy one?
>
> Answers in the matlab interface are preferred.
>
>
> _________________________________________________________________
>
> http://clk.atdmt.com/UKM/go/msnnkmgl0010000002ukm/direct/01/