# Problem with stiffnes matrix and load vector

**URL:** <https://fenicsproject.discourse.group/t/problem-with-stiffnes-matrix-and-load-vector/5905>\
**Category:** variational formulation\
**Created:** [May 28, 2021, 11:32pm UTC](https://fenicsproject.discourse.group/t/problem-with-stiffnes-matrix-and-load-vector/5905 "2021-05-28T23:32:03Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Mondragon](https://avatars.discourse-cdn.com/v4/letter/m/d2c977/32.png) [@Mondragon](https://fenicsproject.discourse.group/u/Mondragon)\
**Post date:** [May 28, 2021, 11:32pm UTC](https://fenicsproject.discourse.group/t/problem-with-stiffnes-matrix-and-load-vector/5905/1 "2021-05-28T23:32:03Z")

</div>

Hello,

I am working on POD decomposition and for obtaining the interpolate solution I need the stiffness matrix and load vector but doing assemble and applying the boundaries conditions I get a wrong stiffness matrix. I don’t if it because the Dolfin stiffness matrix is sorted out using a local DOF or why but I obtaining a wrong all the time. I want the stiffness matrix for operating using numpy matrices. How can I get the stiffness matrix in global coordinates?

Thank you in advance