# How to compute the solution gradient on the boundary

**URL:** <https://bempp.discourse.group/t/how-to-compute-the-solution-gradient-on-the-boundary/73>\
**Category:** Uncategorized\
**Created:** [10 April 2021 01:47 UTC](https://bempp.discourse.group/t/how-to-compute-the-solution-gradient-on-the-boundary/73 "2021-04-10T01:47:57Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![arovinelli](https://avatars.discourse-cdn.com/v4/letter/a/ee59a6/32.png) [@arovinelli](https://bempp.discourse.group/u/arovinelli)\
**Post date:** [10 April 2021 01:47 UTC](https://bempp.discourse.group/t/how-to-compute-the-solution-gradient-on-the-boundary/73/1 "2021-04-10T01:47:57Z")

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Hi there,  
I need to compute what is generally referred to as du/dn. Using some math I can get away with it by computing grad(u) \dot n . However, i can’t find any operator/API computing either the former or the latter.  
Am I missing something. Ideally, grad(u) should be readily available if one uses shape functions.  
Am I missing something?