# Potential bug with setting variable bounds with a NamedArray
**URL:** https://discourse.julialang.org/t/potential-bug-with-setting-variable-bounds-with-a-namedarray/102359
**Category:** Optimization (Mathematical)
**Created:** [August 1, 2023, 4:07pm UTC](https://discourse.julialang.org/t/potential-bug-with-setting-variable-bounds-with-a-namedarray/102359 "2023-08-01T16:07:48Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Mitch\_Phillipson](https://discourse.julialang.org/u/Mitch_Phillipson)
#### Post date: [August 1, 2023, 4:07pm UTC](https://discourse.julialang.org/t/potential-bug-with-setting-variable-bounds-with-a-namedarray/102359/1 "2023-08-01T16:07:48Z")
Hello,
I think I’ve found a small bug in JuMP (or NamedArrays) when setting bounds using a NamedArray
```julia
using JuMP
using NamedArrays
S = [:a,:b]
X = NamedArray([1, 2],S)
m = Model()
@variable(m,Y[S])
set_upper_bound.(Y,X)
```
This throws `DimensionMismatch: arrays could not be broadcast to a common size; got a dimension with lengths 2 and 2`
Both of the following commands work as expected
```julia
set_upper_bound.(Y,X.array)
set_upper_bound.(Y.data,X)
```
I’m not sure if the issue is with JuMP or NamedArrays.
Thanks,
Mitch
---
### Author:  [@Mitch\_Phillipson](https://discourse.julialang.org/u/Mitch_Phillipson)
#### Post date: [August 1, 2023, 7:01pm UTC](https://discourse.julialang.org/t/potential-bug-with-setting-variable-bounds-with-a-namedarray/102359/2 "2023-08-01T19:01:14Z")
I’ve realized this can be expressed more simply as
```julia
using JuMP
using NamedArrays
L = NamedArray([1,2,3],[:a,:b,:c])
X = JuMP.Containers.DenseAxisArray([1,2,3],[:a,:b,:c])
X .≈ L
```
This produces the same error for the same reasons.
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [August 1, 2023, 9:53pm UTC](https://discourse.julialang.org/t/potential-bug-with-setting-variable-bounds-with-a-namedarray/102359/3 "2023-08-01T21:53:37Z")
This is a problem with the way that Julia packages compose. In this case, there are no methods to coordinate JuMP’s `DenseAxisArray` with `NamedArray`.
One approach might be a package extension, like we recently merged for `DimensionalData`: [Add DimensionalData extension by odow · Pull Request #3413 · jump-dev/JuMP.jl · GitHub](https://github.com/jump-dev/JuMP.jl/pull/3413). See the much larger backstory at [[Containers] support ArrayInterface.jl traits · Issue #3214 · jump-dev/JuMP.jl · GitHub](https://github.com/jump-dev/JuMP.jl/issues/3214).
Why use `NamedArray` in the first place? Why not just something like `X = Containers.DenseAxisArray([1, 2], S)`.
---
### Author:  [@Mitch\_Phillipson](https://discourse.julialang.org/u/Mitch_Phillipson)
#### Post date: [August 1, 2023, 10:19pm UTC](https://discourse.julialang.org/t/potential-bug-with-setting-variable-bounds-with-a-namedarray/102359/4 "2023-08-01T22:19:58Z")
That makes sense. And I’ve wanted to experiment with package extensions.
One reason for named arrays vs dense axis arrays is, at least to my knowledge, you can’t mask a dense axis arrays. In your example I don’t believe `X[X>1]` works.
I’m on a phone so apologies if things format poorly or that example does actually work.