# Can't extract A matrix from a problem

**URL:** <https://community.freefem.org/t/cant-extract-a-matrix-from-a-problem/4288>\
**Category:** General Discussion\
**Created:** [May 26, 2026, 11:53am UTC](https://community.freefem.org/t/cant-extract-a-matrix-from-a-problem/4288 "2026-05-26T11:53:23Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![oldoldman](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/oldoldman/32/2725_2.png) [@oldoldman](https://community.freefem.org/u/oldoldman)\
**Post date:** [May 26, 2026, 11:53am UTC](https://community.freefem.org/t/cant-extract-a-matrix-from-a-problem/4288/1 "2026-05-26T11:53:23Z")

</div>

Hi guys,

have a look at the following script

```auto
problem p(...) = ...;
matrix m = p;

```

report error

```auto
Sorry no way to plot this kind of data

```

cann’t extract A matrix and the error is totally confusing. Any suggestion?