# Evaluate\_basis\_all in dolfinx

**URL:** https://fenicsproject.discourse.group/t/evaluate-basis-all-in-dolfinx/3968
**Category:** dolfinx
**Created:** [August 20, 2020, 8:15am UTC](https://fenicsproject.discourse.group/t/evaluate-basis-all-in-dolfinx/3968 "2020-08-20T08:15:15Z")
**Posts on this page:** 1
**Showing post:** 24

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### Author: ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)
#### Post date: [March 25, 2024, 7:28am UTC](https://fenicsproject.discourse.group/t/evaluate-basis-all-in-dolfinx/3968/24 "2024-03-25T07:28:24Z")

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Please note that your specification of versions doesn’t make sense, as

> [@Xijan](#):
>
> I am using Dolfinx 0.8 and Fenicsx 0.7

DOLFINx and FEniCSx represents the same package.  
Here is an updated example for v0.7.x

```python
from mpi4py import MPI
import dolfinx
import ufl
import numpy as np
domain = dolfinx.mesh.create_unit_square(MPI.COMM_WORLD, 1, 1)
tdim = domain.topology.dim
V = dolfinx.fem.FunctionSpace(domain, ("CG", 2))

point = np.array([[0.2, 0.3, 0]])
bb = dolfinx.geometry.bb_tree(domain, tdim)
bbox_collisions = dolfinx.geometry.compute_collisions_points(bb, point)
cells = dolfinx.geometry.compute_colliding_cells(
    domain, bbox_collisions, point)
cell = cells.links(0)[0]

cmap = domain.geometry.cmaps[0]
geom_dofs = domain.geometry.dofmap[cell]
x_ref = cmap.pull_back(point, domain.geometry.x[geom_dofs])

n = ufl.as_vector([0.1, 0.2])
expr = ufl.inner(ufl.grad(ufl.TestFunction(V)), n)
E = dolfinx.fem.Expression(expr, x_ref)
grad_u_at_x_ref = E.eval(domain, [cell])
print(
    f"Cell: {cell}, Point: {point}, x_ref: {x_ref}, grad(u)*n {grad_u_at_x_ref}")

```

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