dolfin team mailing list archive

[Johan Hake <johan.hake@xxxxxxxxx>]

Update your repo and try!

The ufc::cell version of evaluate_basis_all is not usable in Python. You need 
a dolfin::Cell version, which I just added ;) 

We should probably ignore all the ufc::cell versions, and add unit test for 
the one we do expose...

Johan

On Wednesday April 20 2011 15:55:30 Neilen Marais wrote:
> 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 &'
> 
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