# Interpolation in high-order spaces

Hi,

I want to interpolate a function into a Lagrange space of large polynomial order k. For k>9 the programme (see for example the code below) crushes (on my personal computer and on the computer in my university as well, both with dolfin version 2019.1.0). Is this a bug and is there a way to circumvent this issue?

Best regards,
Johannes

from dolfin import *
mesh = UnitSquareMesh(2,2)
V = FunctionSpace(mesh,‘P’,9)
print(‘Interpolate’)
v = interpolate(Constant(1.0), V)
print(v([0.5,0.5]))
V = FunctionSpace(mesh,‘P’,10)
print(‘Interpolate’)
v = interpolate(Constant(1.0), V)
print(v([0.5,0.5]))

The segfault seems to happen during the evaulation of the function, not the interpolation. The function compute_vertex_values() works though.

``````from dolfin import *
import numpy as np

mesh = UnitSquareMesh(5,5)

V = FunctionSpace(mesh,'CG', 9)
W = FunctionSpace(mesh,'CG', 11)

g = Expression('1.0', degree = 1)

v = interpolate(g, V)
print(v(0.5,0.5))
w = interpolate(g, W)
print(w.vector()[:])
print(w.compute_vertex_values())
``````