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["B. Emek Abali" <question152662@xxxxxxxxxxxxxxxxxxxxx>]

New question #152662 on DOLFIN:
https://answers.launchpad.net/dolfin/+question/152662

if I want to use an expression or its derivative

V=VectorFunctionSpace(...)
v=Function(V)
z=variable(v)
a=det(grad(v))
Da=diff(a,z)
form = v[i]*Da[i]*dx

it is fine, but if the expresion is a constant

b=10.0
Db=diff(b,z)
form = v[i]*Db[i]*dx

the diff() returns a Zero and thus raise an error
TypeError: unsupported operand type(s) for +: 'set' and 'tuple'

How should I define the constant expression that it differentiates as a list with three zeros?

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