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[Marie Rognes <meg@xxxxxxxxx>]

I have a slightly interesting issue, possibly with interpolate:

Say I have a RT_0 function u. I want to interpolate this function onto a 
DG_1 function Pi_u.
Since RT_0 \subset DG_1, I would expect to get the same function. This 
does not seem
to be the case at the moment.


||u||_0 =  1.12846688033
||Pi_u||_0 =  1.2624381173

being the output of:

from dolfin import *

mesh = UnitSquare(2, 2)

V_h = FunctionSpace(mesh, "RT", 0)
u = Function(V_h, ("pow(x[0],2)", "1.0"))
u.interpolate()
print "||u||_0 = ", norm(u)

W_h = VectorFunctionSpace(mesh, "DG", 1)
Pi_u = Function(W_h)
Pi_u.interpolate(u)
print "||Pi_u||_0 = ", norm(Pi_u)


(Tested both using tensor and quadrature representation.
Tensor and quad differ somewhat for the norm(u).
Is the quadrature default to integrate RTs using
"too low" a quadrature rule still?)



--
Marie