dolfin team mailing list archive

[Jack <question105698@xxxxxxxxxxxxxxxxxxxxx>]

New question #105698 on DOLFIN:
https://answers.launchpad.net/dolfin/+question/105698

Dear all

I'm trying to solve the following problem:

-d/dx(du/dx) - (du/dx)^3 = 0   on 0 < x < 1

subject to the following bcs:

@ x= 0:    du/dx + u = 3/sqrt(2)
@ x = 1:   du/dx = 0.5

I have in my ufl file:
L  = inner(grad(v), grad(u))*dx - v*( (u.dx(0))**3 )*dx - v*((1.5*sqrt(2)-u))*ds(0) - v*(0.5)*ds(1) 

I assume that ufl doesn't know about the boundaries, so in main.cpp, I have marked them like so:
MeshFunction<dolfin::uint> boundaries(mesh, mesh.topology().dim()-1);
	
	LeftNeumannBoundary boundaryL;
	boundaryL.mark(boundaries, 0);
	
	RightNeumannBoundary boundaryR;
	boundaryR.mark(boundaries, 1);

The problem is how to use the VariationalProblem class. It requires the dirichlet bc, the cell_domains, the interior and exterior_facet_domains.

How can I use VariationalProblem without specifying the dirichlet bc?

Thanks

Jack

-- 
You received this question notification because you are a member of
DOLFIN Team, which is an answer contact for DOLFIN.