# Problems using NtD operator

**URL:** <https://bempp.discourse.group/t/problems-using-ntd-operator/128>\
**Category:** Bempp\
**Created:** [25 March 2022 09:56 UTC](https://bempp.discourse.group/t/problems-using-ntd-operator/128 "2022-03-25T09:56:45Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Gustavo](https://yyz2.discourse-cdn.com/free1/user_avatar/bempp.discourse.group/gustavo/32/36_2.png) [@Gustavo](https://bempp.discourse.group/u/Gustavo)\
**Post date:** [25 March 2022 09:56 UTC](https://bempp.discourse.group/t/problems-using-ntd-operator/128/1 "2022-03-25T09:56:46Z")

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Solved by pulling the latest docker image.

Thanks

* * *

Hi,

I have the following line of code in my notebook:

```python
ntd = bempp.api.operators.boundary.helmholtz.osrc_ntd(space, k)

```

and it gives me the following error:

**AttributeError: module ‘bempp.api.operators.boundary.helmholtz’ has no attribute 'osrc\_ntd’**

However, according to this [documentation](https://bempp-cl.readthedocs.io/en/latest/docs/bempp/api/operators/boundary/helmholtz/index.html#bempp.api.operators.boundary.helmholtz.osrc_ntd) this operator exists.

What am I missing?

Thanks in advance,  
Gustavo

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<div class="post-metadata">

**Author:** ![mscroggs](https://yyz2.discourse-cdn.com/free1/user_avatar/bempp.discourse.group/mscroggs/32/3_2.png) [@mscroggs](https://bempp.discourse.group/u/mscroggs)\
**Post date:** [25 March 2022 10:48 UTC](https://bempp.discourse.group/t/problems-using-ntd-operator/128/2 "2022-03-25T10:48:48Z")

</div>

What version of Bempp are you using? I believe the OSRC operators have been added since the last official release so might be missing if you installed from conda/pip/etc.

---

<div class="post-metadata">

**Author:** ![Gustavo](https://yyz2.discourse-cdn.com/free1/user_avatar/bempp.discourse.group/gustavo/32/36_2.png) [@Gustavo](https://bempp.discourse.group/u/Gustavo)\
**Post date:** [25 March 2022 12:03 UTC](https://bempp.discourse.group/t/problems-using-ntd-operator/128/3 "2022-03-25T12:03:57Z")

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I’m using the version in this docker container:

```auto
docker pull bempp/cl-notebook:latest

```

Bempp\_cl-0.2.4-py3.9.egg (0.2.4)