[Getdp] ... Formulation question ...

Olivier Castany castany at quatramaran.ens.fr
Thu Mar 1 22:43:42 CET 2007


Hello,

your formulation probably contains a term like :

Galerkin { [ Dof{d Phi} , {d Phi} ] ; ... }			(1)

which makes it possible to build a matrix equation. 
You can then add a term :

Galerkin{ [ Spd[] * Norm[{d Phi}]  , {Phi} ] ; ... }		(2)

and solve the problem recursively with a non-linear scheme 
(InitSolution, IterativeLoop, GenerateJac, SolveJac).

> However, if I leave out the Dof{} term, won't that mean that Phi is no  
> longer treated as a variable to be solved for, but rather as something  
> given already? In other words, I won't be solving the right problem?

This is the point of the recursive scheme (InitSolution, IterativeLoop, 
GenerateJac, SolveJac)

* First iteration : 

Phi has been initialized. The default initial value is : Phi = 0 
everywhere (but another initial value can be given in the "Constraint" 
section with "Type Init")

The value of the field "Spd[] * Norm[{d Phi}]" in eq. (2) is 0.

The matrix equation is then solved and you get a field Phi.

* Second iteration :

The value of the field "Spd[] * Norm[{d Phi}]" in eq. (2) is calculated 
based on the result of the first iteration.

The matrix equation is then solved and you get another field Phi.

* Third iteration ... ...

If you're lucky, the process converges to a fixed point which is your 
solution.

Regards,

O.C.