# Matrix formation to store time history

**URL:** <https://community.freefem.org/t/matrix-formation-to-store-time-history/1444>\
**Category:** General Discussion\
**Created:** [January 18, 2022, 8:19am UTC](https://community.freefem.org/t/matrix-formation-to-store-time-history/1444 "2022-01-18T08:19:04Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![zese](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/zese/32/917_2.png) [@zese](https://community.freefem.org/u/zese)\
**Post date:** [January 18, 2022, 8:19am UTC](https://community.freefem.org/t/matrix-formation-to-store-time-history/1444/1 "2022-01-18T08:19:04Z")

</div>

Dear all

I have an iterative process in which for a time period I have to store velocity and pressure field in every time step and then I have a huge matrix having all the information of velocity and pressure to solve the next equation.

how can I define such a matrix?

BR