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[Neilen Marais <nmarais@xxxxxxxxx>]

Hi,

I'm trying to access the elemental basis functions directly through
dolfin in python. I think I've managed it, but for some reason I can't
get evaluate_basis_all() to work. In the code below the commented
for-loop calling evaluate_basis() works fine, but the
evaluate_basis_all() form doesn't work. As far as I can tell the only
difference between the two calls should be the shape of the value
array and omission of the basis function number from
evaluate_basis_all()'s signature. What am I doing wrong here?

Thanks
Neilen

from __future__ import division

import numpy as N
import dolfin as dol
from dolfin import Point, PointSource

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

# Define basis and bilinear form
u = dol.TrialFunction(V)
v = dol.TestFunction(V)
source_coords = N.array([1/1.5, 1/1.5, 1/2], dtype='d')
source_pt = Point(*source_coords)

cell_index = 0
c = dol.Cell(mesh, cell_index)
# Check that the source point is in this element
assert(c.intersects_exactly(source_pt))

finite_element = V.element()
no_basis_fns = finite_element.space_dimension()
# Vector valued elements have rank of 1
assert(finite_element.value_rank() == 1)
# Vector valued elements have only one rank (i.e. 0) along which
# dimensions are defined. This is the dimension that the basis
# function value vector is. Since we have 3D Nedelec elements here
# this should be 3
bf_value_dimension = finite_element.value_dimension(0)
el_basis_vals = N.zeros((no_basis_fns, bf_value_dimension), dtype='d')

## calling evaluate_basis() in loop below works
# for i in range(no_basis_fns):
#     finite_element.evaluate_basis(i, el_basis_vals[i,:], source_coords, c)
finite_element.evaluate_basis_all(el_basis_vals, source_coords, c)

Running this gives me the following error:

/tmp/python-1810o1R.py in <module>()
     32 bf_value_dimension = finite_element.value_dimension(0)
     33 el_basis_vals = N.zeros((no_basis_fns, bf_value_dimension), dtype='d')
     34 # for i in range(no_basis_fns):

     35 #     finite_element.evaluate_basis(i, el_basis_vals[i,:],
source_coords, c)

---> 36 finite_element.evaluate_basis_all(el_basis_vals, source_coords, c)

TypeError: in method 'FiniteElement_evaluate_basis_all', argument 4 of
type 'ufc::cell const &'