On Sun, 14 May 2017 at 21:12 Anna Kalogirou <A.Kalogirou@leeds.ac.uk> wrote:

Dear team,

I am facing a few problems with the real function space, again. I can’t seem to be able to interpolate on a real function, either with a C string expression or UFL. The following sample code

from firedrake import *

mesh = IntervalMesh(10, 1.0)

V = FunctionSpace(mesh, "CG", 1)

V_R = FunctionSpace(mesh, "R", 0)

h = Function(V)

Z = Function(V_R)

x = SpatialCoordinate(V.mesh())

h = interpolate(x[0], V)

Z = interpolate(Expression("1.0"), V_R)

Z = interpolate(1.0, V_R)

gives the error

Traceback (most recent call last):

File "interpolation_reals.py", line 17, in <module>

Z = interpolate(Expression("1.0"), V_R)

File "/Users/matak/firedrake/src/firedrake/firedrake/interpolation.py", line 40, in interpolate

return Interpolator(expr, V, subset=subset).interpolate()

File "/Users/matak/firedrake/src/firedrake/firedrake/interpolation.py", line 60, in __init__

self.callable = make_interpolator(expr, V, subset)

File "/Users/matak/firedrake/src/firedrake/firedrake/interpolation.py", line 129, in make_interpolator

subset))

File "/Users/matak/firedrake/src/firedrake/firedrake/interpolation.py", line 189, in _interpolator

args.append(dat(op2.WRITE, V.cell_node_map()[op2.i[0]]))

TypeError: 'NoneType' object has no attribute '__getitem__'

I assume this functionality hasn’t been added for the real function space?

What does interpolation into R even mean? In general interpolating an expression into a FunctionSpace means evaluating the nodes of the FunctionSpace on the expression. Thus far we haven't actually even defined a Node for R (I guess integral over the domain normalised by domain volume might be it...)

Also, I noticed that when the UFL expression doesn’t include a coordinate x, e.g. in h = interpolate(1.0, V), I get the error:

Traceback (most recent call last):

File "interpolation_reals.py", line 23, in <module>

h = interpolate(1.0, V)

File "/Users/matak/firedrake/src/firedrake/firedrake/interpolation.py", line 40, in interpolate

return Interpolator(expr, V, subset=subset).interpolate()

File "/Users/matak/firedrake/src/firedrake/firedrake/interpolation.py", line 60, in __init__

self.callable = make_interpolator(expr, V, subset)

File "/Users/matak/firedrake/src/firedrake/firedrake/interpolation.py", line 94, in make_interpolator

assert isinstance(expr, ufl.classes.Expr)

AssertionError

Actually, as the error says, this error is because you need to pass a UFL expression into interpolate and 1.0 isn't a UFL expression.

interpolate(Constant(1.0), V)

would work fine.

Furthermore, I’m having trouble the exponential UFL expression, e.g.

exp_h = interpolate(exp(x[0]), V)

TypeError: nb_float should return float object

I am unable to reproduce this problem. To be precise, ran the following script. It executed without error and printed what appears to be the right answer:

from firedrake import *

mesh = IntervalMesh(10, 1.0)

V = FunctionSpace(mesh, "CG", 1)

x = SpatialCoordinate(V.mesh())

exp_h = interpolate(exp(x[0]), V)

print exp_h.dat.data_ro

Thank you very much for your help,

Anna.

P.S. At the start of every simulation, the following sentence is printed twice and delays the simulation for a couple of seconds:

[warn] kq_init: detected broken kqueue; not using.: No such file or directory

What does it mean and can we get rid of it?

The error message is some Mac issue. I see it too but I have no idea what causes it. I am not convinced that it causes any delay at all. It's simply the case that loading firedrake is not completely instantaneous.

Regards,

David