dolfin team mailing list archive

[kent-and@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
>

That would be great. I think a simple check on the value shape and
the tuples is sufficient.

Kent




>> 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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>