# Global constraints in functions
**URL:** https://discourse.julialang.org/t/global-constraints-in-functions/26341
**Category:** Optimization (Mathematical)
**Created:** [July 14, 2019, 12:45pm UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341 "2019-07-14T12:45:26Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@MuadhF](https://discourse.julialang.org/u/MuadhF)
#### Post date: [July 14, 2019, 12:45pm UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341/1 "2019-07-14T12:45:26Z")
Hi,
I declared some constraints in a function because I needed an if condition, and wanted to know if I can somehow make these constraints defined outside the function as well. Here’s part of the function:
```julia
function amortization(z)
if z == 0
@constraints(m, begin
int[t = 1:T], γ[t] == k * ( δ0 - (t-1) * A )
pay[t = 1:T], δ[t] == A + γ[t]
end)
```
So in this case, is there any way to edit this so that `int` and `pay` can be referred to, outside the function?
Thanks!
---
### Author:  [@tkoolen](https://discourse.julialang.org/u/tkoolen)
#### Post date: [July 14, 2019, 1:24pm UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341/2 "2019-07-14T13:24:27Z")
`return int, pay`?
---
### Author:  [@MuadhF](https://discourse.julialang.org/u/MuadhF)
#### Post date: [July 15, 2019, 5:42am UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341/3 "2019-07-15T05:42:00Z")
I’m getting an error
```julia
UndefVarError: pay not defined
```
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [July 15, 2019, 3:31pm UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341/4 "2019-07-15T15:31:30Z")
See the JuMP documentation:
[http://www.juliaopt.org/JuMP.jl/v0.19.2/variables/#What-is-a-JuMP-variable?-1](http://www.juliaopt.org/JuMP.jl/v0.19.2/variables/#What-is-a-JuMP-variable?-1)
[http://www.juliaopt.org/JuMP.jl/v0.19.2/constraints/](http://www.juliaopt.org/JuMP.jl/v0.19.2/constraints/)
You can query named variables and constraints using a symbol.
You can do this:
```nohighlight
function add_variable(model)
@variable(model, x)
end
function add_constraint(model)
x = model[:x]
@constraint(model, con, 2 * x <= 1)
end
model = Model()
add_variable(model)
add_constraint(model)
x = model[:x]
con = model[:con]
```
Or
```nohighlight
function add_constraint(model, x)
@constraint(model, con, 2 * x <= 1)
return con
end
model = Model()
@variable(model, x)
con = add_constraint(model, x)
```
---
### Author:  [@MuadhF](https://discourse.julialang.org/u/MuadhF)
#### Post date: [July 16, 2019, 7:56am UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341/5 "2019-07-16T07:56:49Z")
Thank you, that helped!
---
### Author:  [@MuadhF](https://discourse.julialang.org/u/MuadhF)
#### Post date: [July 16, 2019, 12:39pm UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341/6 "2019-07-16T12:39:41Z")
Just a quick question, would this method work for multiple constraints? Thanks
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [July 16, 2019, 1:37pm UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341/7 "2019-07-16T13:37:13Z")
Yes.
```nohighlight
function foo(model)
@variable(model, x[i=1:2])
@constraint(model, con[i=1:2], x[i] <= 2)
end
model = Model()
foo(model)
x = model[:x]
con = model[:con]
x[1]
con[2]
```
---
### Author:  [@MuadhF](https://discourse.julialang.org/u/MuadhF)
#### Post date: [July 17, 2019, 6:00am UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341/8 "2019-07-17T06:00:24Z")
Awesome, thanks!