# Interpolate expression with complex litteral

**URL:** <https://fenicsproject.discourse.group/t/interpolate-expression-with-complex-litteral/8251>\
**Category:** dolfinx\
**Created:** [May 5, 2022, 1:24pm UTC](https://fenicsproject.discourse.group/t/interpolate-expression-with-complex-litteral/8251 "2022-05-05T13:24:20Z")\
**Posts on this page:** 1\
**Showing post:** 4

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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:** [May 5, 2022, 3:05pm UTC](https://fenicsproject.discourse.group/t/interpolate-expression-with-complex-litteral/8251/4 "2022-05-05T15:05:25Z")

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> [@Calva](#):
>
> `expr = 1j * u`

Could you try with `dolfinx.fem.Constant(mesh, PETSc.ScalarType(1j))*u`?

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