# Problems with distributed package

**URL:** https://discourse.julialang.org/t/problems-with-distributed-package/113893
**Category:** General Usage
**Tags:** package, parallel, memory-allocation, distributed
**Created:** [May 6, 2024, 10:18am UTC](https://discourse.julialang.org/t/problems-with-distributed-package/113893 "2024-05-06T10:18:36Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![greivin](https://avatars.discourse-cdn.com/v4/letter/g/a6a055/32.png) [@greivin](https://discourse.julialang.org/u/greivin)
#### Post date: [May 6, 2024, 10:18am UTC](https://discourse.julialang.org/t/problems-with-distributed-package/113893/1 "2024-05-06T10:18:37Z")

</div>

I have been having troubles using the Distributed package. I have one function that returns a 100 x 4 array. This array is produced by averaging over some dimensions of a SharedArray that is constructed with a distributed for, the code looks something like

```julia
@everywhere function GenerateMatrix(H::sparsearray, indices::Array{Int}, a::Float64)
   Gavg = SharedArray{Float64}(100, length(indices))
   Z = Array{Float64}(undef, 100, 4)
   G = lu(a*sparse(I, size(H)) - H) #new array, same size as H
   @sync @distributed for i=1:length(indices)
          main_ind = indices[i]
          Gmain = G[:, main_ind]
           ...
          #Other for operations that fill the matrix Gavg
    end
    Z[:,1] = mean(G_avg, dims=2)
    #And other operations up to Z[:,4]
    return Z
 end

```

This function has no problems whatsover by itself, the problem comes when I try to generate several of these Z arrays and average them over and over, rewriting the same file and saving as checkpoints every factor of 1000, as follows

```julia
using DelimitedFiles
function IterateFiles(a::Float64, N)
        for j=1:N
             ...
             #Create H and the respective indices vector
             Z = GenerateMatrix(H, indices, a)
             if j==1
                 writedlm("Z_sample"*string(j), Z)
             else
                Zprev = readdlm("Z_sample"*string(j-1))
                Ztemp = (Zprev *(j-1)+ Z)/j  
                writedlm("Z_sample"*string(j), Ztemp)
                if (j-1)%1000 != 0 #this deletes the previous file unless it corresponds to a checkpoint
                   rm("Z_sample"*string(j-1)) 
                end
        end

```

This code excutes just fine and produce files as expected, however it stops producing files after (a random number) of several iterations of the function `IterateFiles`. It does not produce an error message. When I check the workers with `ps auxr` in the terminal, at the beginning shows that the program is working just fine and the selected number of processors with the distributed are being used, but a bit after `ps auxr` just displays the original instruction sent but no other workers from the distributed, and after this happens no new files are produced.

I though it was an memory error but that doesn’t seem to be the problem. There’s no error message nor the main instruction to run the code stops, `julia -p 8 code.jl` still appears as an outgoing work but is no longer producing results.

I have no clue of what can be going on. I’d greatly appreciate any insight or help you can provide to this.