Julia Vscode new version issue with JuMP

Specific Domains Optimization (Mathematical)
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1

I’m having a problem with SparsesAxisArray JuMP on Julia for Vscode.
When I use @variable with this condition below, it reproduces an error

using Gurobi, JuMP

model = Model(Gurobi.Optimizer) 

n = 5
V = 1:n
V0= 1:n+1

@variable(model, x[i in V0, j in V; i != j], Bin) #this not work

Defines: JuMP.Containers.SparseAxisArray{VariableRef,2,Tuple{Int64,Int64}} with 25 entries:
but in the end, reproduces:

Internal Error: ERROR: MethodError: no method matching size(::JuMP.Containers.SparseAxisArray{VariableRef,2,Tuple{Int64,Int64}})
Closest candidates are:
  size(::AbstractArray{T,N}, ::Any) where {T, N} at abstractarray.jl:38
  size(::BitArray{1}) at bitarray.jl:99
  size(::BitArray{1}, ::Integer) at bitarray.jl:103

I figured out that if i return to previous version 0.15.40 of Julia package on Vscode, this code works perfectly. Any suggestions?

Thanks in advance!

2

I’d argue this is a bug in JuMP, because

julia> @variable(model, x[i in V0, j in V; i != j], Bin) isa AbstractArray
true

and size is part of the AbstractArray interface.

That said, showing those internal errors makes the REPL kinda unusable, so we’ll stop doing that in the extension.

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3

There is an open issue for size: https://github.com/jump-dev/JuMP.jl/issues/2117

We need to spend some time re-thinking the functionality of the SparseAxisArray, because it is partially an array, and partially a dictionary.

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4

I don’t understand where the error comes from. Why do you need to call size in your example ?

@pfitzseb We could implement size and axis for SparseAxisArray but that would require a little bit of bookkeeping and we have no convincing use case yet. Accessing it with the axis would not be a good idea anyway since it is sparse hence one should not go through the cartesian product of the axis.

5

The error comes from VSCode trying to display that object as an AbstractArray by showing its contents in a tree view like this:
image

Also see Stop showing user errors for workspace in REPL · Issue #1491 · julia-vscode/julia-vscode · GitHub.

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