dolfin team mailing list archive

[Johan Hake <hake@xxxxxxxxx>]

On Tuesday 22 September 2009 09:49:38 kent-and@xxxxxxxxx wrote:
> The following variational forms should produce the same matrices,
> 
> Ai = Function(T, ( ("1.0", "0.0"), ("0.0", "1.0")) )
> a1 = dot(dot(Ai, curl(v)), curl(u))*dx
> a2 = dot(curl(v), curl(u))*dx
> 
> But it doesn't.
> 
> I am not sure whether the bug is in Dolfin, FFC or UFL.
> 
> The following test script can be used to test the problem.
> 
> from dolfin import *
> 
> N = 2
> mesh = UnitCube(N,N,N)
> V = FunctionSpace(mesh, "N1curl", 1)
> T = TensorFunctionSpace(mesh, "CG", 1)
> 
> u = TrialFunction(V)
> v = TestFunction(V)
> 
> Ai = Function(T, ( ("1.0", "0.0"), ("0.0", "1.0")) )

This creates a 2x2 tensor function, do you not want a 3x3 tensor?

I have plans on fixing rigorous tests for value shapes for function 
expressions. Which are automatically checked with the value shape of the 
FunctionSpace. This could prevent your error and some nasty segfaults...

Johan

> a1 = dot(dot(Ai, curl(v)), curl(u))*dx
> a2 = dot(curl(v), curl(u))*dx
> 
> A1 = assemble(a1)
> A2 = assemble(a2)
> 
> 
> file = File("A1.m")
> file <<A1
> file = File("A2.m")
> file <<A2
> 
> file_str = """
> A1;
> A1 = A;
> clear A;
> A2;
> A2 = A;
> clear A;
> 
> max(max(A1-A2))
> """
> 
> f = open("test_tensor.m", 'w')
> f.write(file_str)
> f.close()
> 
> import os
> os.system("octave test_tensor.m")
> 
> 
> 
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