Hi,

I have a variable that is supposed to be a matrix. Its size should depend on another variable, which also should be optimized, or at least changed throughout the optimization process:

```
@variable(model, n,lower_bound = 0,integer = true)
@variable(model, NodeMatrix[1:20,1:n],lower_bound = 0,integer = true)
```

I get this result if I try to link the variables.

```
ERROR: MethodError: no method matching (::Colon)(::Int64, ::VariableRef)
Closest candidates are:
Any(::T, ::Any, ::T) where T<:Real at range.jl:41
Any(::A, ::Any, ::C) where {A<:Real, C<:Real} at range.jl:10
Any(::T, ::Any, ::T) where T at range.jl:40
...
Stacktrace:
[1] top-level scope at C:\Users\Keven\.julia\packages\JuMP\e0Uc2\src\macros.jl:91
[2] top-level scope at REPL[6]:1
```

Based on the size of the second dimension of the â€śNodeMatrixâ€ť, my program yields different results.

Is there a way to link the variables?

Thanks