Hi,

I am running this code using mpirun:

```
import dolfin as dl
from mpi4py import MPI
comm = MPI.COMM_WORLD
mesh = dl.RectangleMesh(comm,dl.Point(0,0),dl.Point(1,1),100,100)
V = dl.FunctionSpace(mesh,'CG',1)
f = dl.Expression('(1-sin(x[0]))*(1-cos(x[1]))', degree=2)
u = dl.Function(V)
u = dl.project(f,V)
out_boundary = lambda x, on_boundary: on_boundary and dl.near(x[1],1, 1E-14)
```

I would like to evaluate f on the `out_boundary`

and collect this information on `rank=0`

. The issue is that this boundary is shared among all processes. Does anyone know what is the correct way to do this?

Thank you very much for the help.