# EAGO unbounded variables
**URL:** https://discourse.julialang.org/t/eago-unbounded-variables/119865
**Category:** Optimization (Mathematical)
**Created:** [September 25, 2024, 12:59pm UTC](https://discourse.julialang.org/t/eago-unbounded-variables/119865 "2024-09-25T12:59:07Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@kiki\_Van\_Elsen](https://discourse.julialang.org/u/kiki_Van_Elsen)
#### Post date: [September 25, 2024, 12:59pm UTC](https://discourse.julialang.org/t/eago-unbounded-variables/119865/1 "2024-09-25T12:59:07Z")
Hello!
I want to run the following code:
```julia
function bivariate(solver, type)
try
#choose which solver you want to use
m = Model(solver.Optimizer)
#function we want to Optimize
f(x1,x2) = -x1 -x2
#Variables in the optimization model
@variable(m, x1)
@variable(m, x2)
#use piecewiselinear to solve the probem and set method to the type of formulation you want to test
#Logarithmic or MC
z = piecewiselinear(m,
x1,
x2,
#start: step: stop
0: 0.5: 1,
0: 0.5: 1,
(x1, x2) -> (-x1 - x2);
method = type,
)
#constraints of the model
@constraint(m, (x1)^2 + (x2)^2 <= 1)
@constraint(m, 0 <= x1 <= 2)
@constraint(m, 0 <= x2 <= 2)
#objective of the model
@objective(m, Min, z)
#optimize the model
optimize!(m)
value_x1 = value.(x1)
value_x2 = value.(x2)
return true, value_x1, value_x2
catch exeption
println(exeption.msg)
value_x1 = "-"
value_x2 = "-"
return exeption.msg, value_x1, value_x2
end
end
```
Whenever I select EAGO as solver, I get the following warning:
```julia
┌ Warning: At least one branching variable is unbounded. This will interfere with EAGO's global
│ optimization routine and may cause unexpected results. Bounds have been automatically
│ generated at +/- 1e10 for all unbounded variables, but tighter user-defined bounds are
│ highly recommended. To disable this warning and the automatic generation of bounds, use
│ the option `unbounded_check = false`.
└ @ EAGO C:\Users\kikiv\.julia\packages\E
```
However, I cannot find where there would be unbounded variables. Does pieceweiselinear introduce these?
Kind regards,
Kiki
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [September 26, 2024, 5:40am UTC](https://discourse.julialang.org/t/eago-unbounded-variables/119865/2 "2024-09-26T05:40:34Z")
Hi @kiki_Van_Elsen, welcome to the forum 😄
Instead of:
```julia
@variable(m, x1)
@variable(m, x2)
@constraint(m, 0 <= x1 <= 2)
@constraint(m, 0 <= x2 <= 2)
```
do
```julia
@variable(m, 0 <= x1 <= 2)
@variable(m, 0 <= x2 <= 2)
```
Your version is equivalent to
```julia
@variable(m, -Inf <= x1 <= Inf)
@variable(m, -Inf <= x2 <= Inf)
@constraint(m, 0 <= 1.0 * x1 + 0.0 <= 2)
@constraint(m, 0 <= 1.0 * x2 + 0.0 <= 2)
```
JuMP adds variable bounds only if you specify them in `@variable`. We don’t interpret `@constraint(model, x >= 0)` as a variable bound, but as the linear constraint 1 x + 0 \ge 0.
Having said that, depending on the method you choose, `piecewiselinear` might also add unbounded variables.
---
### Author:  [@kiki\_Van\_Elsen](https://discourse.julialang.org/u/kiki_Van_Elsen)
#### Post date: [September 27, 2024, 7:35am UTC](https://discourse.julialang.org/t/eago-unbounded-variables/119865/3 "2024-09-27T07:35:20Z")
Thank you so much!
I now no longer get a warning for the method :MC.
Do you perhaps know why I still get the warning for the Logarithmic method? I do not immediately see what kind of unbounded variable is added there.
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [September 27, 2024, 7:52am UTC](https://discourse.julialang.org/t/eago-unbounded-variables/119865/4 "2024-09-27T07:52:39Z")
I’m not sure. I don’t know the details of the formulation inside PiecewiseLinearOpt.
Note that this is just a warning. You’re probably fine to ignore it.