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[Melanie Jahny <question152076@xxxxxxxxxxxxxxxxxxxxx>]

Question #152076 on DOLFIN changed:
https://answers.launchpad.net/dolfin/+question/152076

    Status: Answered => Open

Melanie Jahny is still having a problem:
Sorry, I just wanted to keep the question text brief.
The code is

mesh = Rectangle(0,0,150,0.29, 750, 20)
mesh.order()

# Define function spaces (P2-P1)
V = VectorFunctionSpace(mesh, "CG", 2) 
W = FunctionSpace(mesh, "CG", 1)   

# combined Function Space
VW = V*W

(u,p) = TrialFunctions(VW)

class InitialConditions(Expression):   
    def __init__(self):        
        random.seed(2 + MPI.process_number())
    def eval(self, values, x):        
        values[0] = 0.02
        values[1] = 0.02
    def value_shape(self):
        return (2,)


I tried now to use a Function for Interpolation:

u_init = InitialConditions()
u_test = Function(V)
u_test.interpolate(u_init)

I get an error message in eval. It works if I change the eval function
in the InitalConditions class:

def eval(self, values, x):        
        values[0] = 0.02

But if I do this, are the two components of the vector valued function
initialized?

And I've got another question:
Can I define the solution of a differential equation as a Function instead of
a TrialFunction?
Can I use u_test now as the solution function?
What is the difference?

Thanks for your help!!!

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