# A problem about JUMP function fix

**URL:** https://discourse.julialang.org/t/a-problem-about-jump-function-fix/80596
**Category:** Optimization (Mathematical)
**Tags:** jump
**Created:** [May 6, 2022, 9:31am UTC](https://discourse.julialang.org/t/a-problem-about-jump-function-fix/80596 "2022-05-06T09:31:16Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![mahon](https://avatars.discourse-cdn.com/v4/letter/m/9e8a1a/32.png) [@mahon](https://discourse.julialang.org/u/mahon)
#### Post date: [May 6, 2022, 9:31am UTC](https://discourse.julialang.org/t/a-problem-about-jump-function-fix/80596/1 "2022-05-06T09:31:16Z")

</div>

Hello , i am trying to use function `fix` to fix a matrix variable

for example

```julia
@variable(model, P_dch[1:2,1:2]);
fix(P_dch, [0 0;0 0]);

```

but it doesn`t work, how can i do ?  
thanks

---

<div class="post-metadata">

### Author: ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [May 6, 2022, 10:06am UTC](https://discourse.julialang.org/t/a-problem-about-jump-function-fix/80596/2 "2022-05-06T10:06:51Z")

</div>

Use broadcasting: `fix.(`

---

<div class="post-metadata">

### Author: ![mahon](https://avatars.discourse-cdn.com/v4/letter/m/9e8a1a/32.png) [@mahon](https://discourse.julialang.org/u/mahon)
#### Post date: [May 6, 2022, 10:08am UTC](https://discourse.julialang.org/t/a-problem-about-jump-function-fix/80596/3 "2022-05-06T10:08:13Z")

</div>

thank you very much