# Interpolate into function, and fail in PETSc vector norm (dolfinx)

**URL:** <https://fenicsproject.discourse.group/t/interpolate-into-function-and-fail-in-petsc-vector-norm-dolfinx/4312>\
**Category:** Linear Algebra\
**Created:** [October 13, 2020, 7:56am UTC](https://fenicsproject.discourse.group/t/interpolate-into-function-and-fail-in-petsc-vector-norm-dolfinx/4312 "2020-10-13T07:56:04Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**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:** [October 13, 2020, 8:28am UTC](https://fenicsproject.discourse.group/t/interpolate-into-function-and-fail-in-petsc-vector-norm-dolfinx/4312/2 "2020-10-13T08:28:49Z")

</div>

Add the line:

```auto
test.vector.ghostUpdate(addv=PETSc.InsertMode.ADD, mode=PETSc.ScatterMode.REVERSE)

```

or

```auto
test.vector.assemble()

```

after interpolation.

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