It would be nice to have a simple example that illustrates the problem and that doesn’t rely on any external packages. Something that can be copy pasted into the REPL.
A CartesianIndex represents an index into a potentially multidimensional array. So I’m not sure what converting it to an integer means. Do you mean how to convert it to a “linear index”?
julia> a = rand(2,2)
2×2 Array{Float64,2}:
0.57097 0.0647051
0.767868 0.531104
julia> I = LinearIndices(a)
2×2 LinearIndices{2,Tuple{Base.OneTo{Int64},Base.OneTo{Int64}}}:
1 3
2 4
julia> I[CartesianIndex(1,2)]
3