# Try to get unset x,y,

**URL:** https://community.freefem.org/t/try-to-get-unset-x-y/584
**Category:** General Discussion
**Created:** [September 17, 2020, 10:59am UTC](https://community.freefem.org/t/try-to-get-unset-x-y/584 "2020-09-17T10:59:43Z")
**Posts on this page:** 6
**Page:** 1

<div class="post-metadata">

### Author: ![candy](https://avatars.discourse-cdn.com/v4/letter/c/67e7ee/32.png) [@candy](https://community.freefem.org/u/candy)
#### Post date: [September 17, 2020, 10:59am UTC](https://community.freefem.org/t/try-to-get-unset-x-y/584/1 "2020-09-17T10:59:43Z")

</div>

Hello，

I am solving a large sysytem, my idea is to decouple it. But my code can be run in 2D, it gives errors in 3D. It says

Try to get unset x,y, …

Did you see some similar error? Could you give me some insights?

---

<div class="post-metadata">

### Author: ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)
#### Post date: [September 17, 2020, 6:03pm UTC](https://community.freefem.org/t/try-to-get-unset-x-y/584/2 "2020-09-17T18:03:23Z")

</div>

No code to reproduce the error =\> not possible to help.

---

<div class="post-metadata">

### Author: ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)
#### Post date: [September 17, 2020, 7:26pm UTC](https://community.freefem.org/t/try-to-get-unset-x-y/584/3 "2020-09-17T19:26:11Z")

</div>

generally you have code like

```
real u;
fespave Vh(Vh,P1); 
Vh uh;
...

```

u = uh; // here you have big mistake u def by the value of uh at the un set current point

---

<div class="post-metadata">

### Author: ![candy](https://avatars.discourse-cdn.com/v4/letter/c/67e7ee/32.png) [@candy](https://community.freefem.org/u/candy)
#### Post date: [September 18, 2020, 1:07am UTC](https://community.freefem.org/t/try-to-get-unset-x-y/584/4 "2020-09-18T01:07:37Z")

</div>

Thank you very much!

---

<div class="post-metadata">

### Author: ![candy](https://avatars.discourse-cdn.com/v4/letter/c/67e7ee/32.png) [@candy](https://community.freefem.org/u/candy)
#### Post date: [September 18, 2020, 1:08am UTC](https://community.freefem.org/t/try-to-get-unset-x-y/584/5 "2020-09-18T01:08:08Z")

</div>

Thanks a lot, I see~

---

<div class="post-metadata">

### Author: ![xiaojiemo](https://avatars.discourse-cdn.com/v4/letter/x/a4c791/32.png) [@xiaojiemo](https://community.freefem.org/u/xiaojiemo)
#### Post date: [September 26, 2021, 7:14am UTC](https://community.freefem.org/t/try-to-get-unset-x-y/584/6 "2021-09-26T07:14:52Z")

</div>

have you solved the error yet?