dolfin team mailing list archive

[Chaffra <question156790@xxxxxxxxxxxxxxxxxxxxx>]

Question #156790 on DOLFIN changed:
https://answers.launchpad.net/dolfin/+question/156790

    Status: Answered => Open

Chaffra is still having a problem:
Thanks for your answers Mikael. I would be interested in knowing more
about the chain rule implementation if you have more info/resources  on
how to do it. Also using you code above I can solve the eikonal equation
for my case but the solution is zero everywhere. I assume this has to do
with the boundary conditions but is there a working demo example I could
work from?

Many thanks,
Chaffra

--new code--

mesh = UnitInterval(51, )

class RefractiveIndex(Expression):
    def eval(self, values,x):
        if x[0]<0.5:
            values[0] = 1.0
        else:
            values[0] = 100.0
            
def light_exposed_area(x, on_boundary):
    return near(x[0],0.0) and on_boundary
light_boundary = AutoSubDomain(light_exposed_area)

#k_markers = MeshFunction("uint", mesh, mesh.topology().dim() - 1)
#k_markers.set_all(0)
#light_boundary.mark(k_markers,1)

Q = FunctionSpace(mesh,'CG',1)
u = Function(Q)
du = TrialFunction(Q)
v = TestFunction(Q)
eps = Constant(0.01)
 
n = RefractiveIndex()
F = inner(grad(u), grad(u))*dx - n**2*v*dx + eps*inner(grad(du),grad(v))*dx
J = derivative(F,u,du)

bc = DirichletBC(Q,Constant(0.0),light_boundary)

problem = VariationalProblem(J,-F, bcs=[bc,])
problem.solve(u)
plot(u)

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