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[Neilen Marais <question152565@xxxxxxxxxxxxxxxxxxxxx>]

Question #152565 on DOLFIN changed:
https://answers.launchpad.net/dolfin/+question/152565

Neilen Marais posted a new comment:
Anders,

I don't think the V.sub works for Nedelec elements. I do:

import dolfin as dol
from dolfin import dot, curl, inner, dx, Point, PointSource

class CavityDims(object): pass
cdims = CavityDims()
cdims.a, cdims.b, cdims.c = 29,23,19

# Define mesh
mesh = dol.UnitCube(1,1,1)
mesh.coordinates()[:] *= [cdims.a,cdims.b,cdims.c]

# Define function space
order = 3
V = dol.FunctionSpace(mesh, "Nedelec 1st kind H(curl)", order)

# Define basis and bilinear form
u = dol.TrialFunction(V)
v = dol.TestFunction(V)
source_pt = Point(cdims.a/2, cdims.b/2, cdims.c/2)

m = inner(v, u)*dx                  # Mass form

M = dol.PETScMatrix()
dol.assemble(m, tensor=M, mesh=mesh)
b = dol.Vector(M.size(0))
b.array()[:] = 0

ps0 = PointSource(V.sub(0), source_pt)
ps1 = PointSource(V.sub(1), source_pt)
ps2 = PointSource(V.sub(2), source_pt)

ps0.apply(b)
ps1.apply(b)
ps2.apply(b)


I get:

/tmp/python-1810_GJ.py in <module>()
     32 b.array()[:] = 0
     33 
---> 34 ps0 = PointSource(V.sub(0), source_pt)
     35 ps1 = PointSource(V.sub(1), source_pt)
     36 ps2 = PointSource(V.sub(2), source_pt)

/home/nmarais/local/lib/python2.6/site-packages/dolfin/functions/functionspace.pyc in sub(self, i)
     98             raise ValueError, "no SubSpaces to extract"
     99         if i >= self.num_sub_spaces():
--> 100             raise ValueError, "Can only extract SubSpaces with i = 0..%d"%(self.num_sub_spaces()-1)
    101         assert(hasattr(self._ufl_element,"sub_elements"))
    102         element = self._ufl_element.sub_elements()[i]

ValueError: Can only extract SubSpaces with i = 0..-1

The error seems to come from the V.sub() call.

also checking

In [25]: V.num_sub_spaces()
Out[25]: 0

Cheers
Neilen

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