Dear all,

I would like to assemble the right hand side of a variational problem which is the integral over a circle of a source term. More precisely, I would like to solve the problem of finding u such that

\int_{\Omega} \nabla u \cdot \nabla v = \int_C{fv},

where \Omega is a square, C is a circle, f is a scalar source term and v is a test function.

To assemble the right hand side, I discretize the circle as a collection of points and, for each one of them, I find the element containing the point. Then I evaluate the (three) basis functions of this element at this particular point using the `evaluate_basis`

function

However, I guess I am doing something wrong because the results I obtain are not correct.

Here is a minimal working example:

```
from fenics import *
import numpy as np
Nx = 10
Ny = 10
mesh = UnitSquareMesh(10,10)
tree = mesh.bounding_box_tree()
N = 10
theta = np.linspace(0,2*np.pi,N)
xc = 0.5
yc = 0.5
rc = 0.1
V = FunctionSpace(mesh, "CG", 1)
elements = V.element()
dofmap = V.dofmap()
for i in range(N):
pt = Point(xc+rc*np.cos(theta[i]), yc + rc*np.sin(theta[i]))
collision = tree.compute_entity_collisions(pt)
for col in collision:
cell = Cell(mesh,col)
coord = elements.tabulate_dof_coordinates(cell)
dof = dofmap.cell_dofs(cell.index())
basis = elements.evaluate_basis(dof[0], np.array([pt[0], pt[1]]), coord, cell.orientation())
print(basis)
```

And this is the result of the evaluation:

```
python mwe_evaluate_basis.py
[-3.79570335e+52]
[-3.79570335e+52]
[6.92943466e-310]
[0.]
[1.e-323]
[1.e-323]
[0.]
[0.]
[2.13436318e-314]
[2.13436318e-314]
[0.]
[0.]
[-3.79570335e+52]
[-3.79570335e+52]
[-3.79570335e+52]
[-3.79570335e+52]
[6.92943452e-310]
[0.]
[1.e-323]
[1.e-323]
```

Any ideas ?