ERROR: LoadError: UndefRefError: access to undefined reference

General Usage
1

So I have the following function

function regionextract(data::Array{<:Real},coord::Array)

    nlon1 = length(coord[1]); nlon2 = size(data,1);
    nlat1 = length(coord[2]); nlat2 = size(data,2);
    nt = size(data)[3:end]; ndim = ndims(data);

    if ndim == 2; data = data[coord[1],coord[2]];
    elseif ndim >= 3;
        data = reshape(data,nlon2,nlat2,:);
        data = data[coord[1],coord[2],:];
        data = reshape(data,Tuple(vcat(nlon1,nlat1,nt...)));
    end

end

However, I have the following error

ERROR: LoadError: UndefRefError: access to undefined reference
Stacktrace:
 [1] getindex at ./array.jl:729 [inlined]
 [2] macro expansion at ./multidimensional.jl:699 [inlined]
 [3] macro expansion at ./cartesian.jl:64 [inlined]
 [4] macro expansion at ./multidimensional.jl:694 [inlined]
 [5] _unsafe_getindex! at ./multidimensional.jl:690 [inlined]
 [6] _unsafe_getindex(::IndexLinear, ::Array{Real,3}, ::UnitRange{Int64}, ::UnitRange{Int64}, ::Base.Slice{Base.OneTo{Int64}}) at ./multidimensional.jl:684
 [7] _getindex at ./multidimensional.jl:670 [inlined]
 [8] getindex at ./abstractarray.jl:981 [inlined]

which I have traced to the line

data = data[coord[1],coord[2],:];

I’ve seen other topics with the same error, but I am not sure if I am doing my types correctly. I’ve checked on both coord[1] and coord[2] and they both give reasonable values that are within the bounds of the data array.

2

It is very likely that you have not initialized elements of coord, but it is hard to say more without a self-contained example. Cf

julia> Array{Any}(undef, 1)[1]
ERROR: UndefRefError: access to undefined reference
Stacktrace:
 [1] getindex(::Array{Any,1}, ::Int64) at ./array.jl:787
 [2] top-level scope at REPL[1]:1
3

What do you mean exactly by coord not being initialized?

coord[1] and coord[2] both exist: doing @info coord[1] gives me 345:456, for example.

4

I was just guessing based on the information you provided. Again, it is hard to say more without an MWE.

5

Update. Seems to be that I defined things in the parent function wrongly :expressionless: so yeah, I think this topic can be closed haha.