# ERROR: LoadError: UndefRefError: access to undefined reference
**URL:** https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683
**Category:** General Usage
**Created:** [January 23, 2020, 5:21am UTC](https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683 "2020-01-23T05:21:19Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@natgeo-wong](https://discourse.julialang.org/u/natgeo-wong)
#### Post date: [January 23, 2020, 5:21am UTC](https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683/1 "2020-01-23T05:21:19Z")
So I have the following function
```julia
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
```julia
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
```julia
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.
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [January 23, 2020, 6:44am UTC](https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683/2 "2020-01-23T06:44:00Z")
It is very likely that you have not initialized elements of `coord`, but it is hard to say more without a [self-contained example](https://discourse.julialang.org/t/psa-make-it-easier-to-help-you/14757). Cf
```julia
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
```
---
### Author:  [@natgeo-wong](https://discourse.julialang.org/u/natgeo-wong)
#### Post date: [January 23, 2020, 7:01am UTC](https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683/3 "2020-01-23T07:01:03Z")
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.
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [January 23, 2020, 8:17am UTC](https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683/4 "2020-01-23T08:17:14Z")
I was just guessing based on the information you provided. Again, it is hard to say more without an MWE.
---
### Author:  [@natgeo-wong](https://discourse.julialang.org/u/natgeo-wong)
#### Post date: [January 24, 2020, 5:59pm UTC](https://discourse.julialang.org/t/error-loaderror-undefreferror-access-to-undefined-reference/33683/5 "2020-01-24T17:59:41Z")
Update. Seems to be that I defined things in the parent function wrongly 😑 so yeah, I think this topic can be closed haha.