Can Shared Arrays handle concurrent writes safely in Julia?

Question

So I was trying to optimize an array operation in Julia, but noticed that I was getting a rather large error on my matrix occasionally. I also noticed that there existed the possibility of concurrently writing to the same index of a SharedArray in Julia. I was wondering if Julia can safely handle it. If not, how may I able able to handle it?

Here is a basic example of my issue

for a list of arbitrary x,y indexes in array J
    j[x,y] += some_value
end

Can Julia handle this case or, like C, will there exist the possibility of overwriting the data. Are their atomic operations in Julia to compensate ffor this?

Answer 1

Shared arrays deliberately have no locking, since locking can be expensive. The easiest approach is to assign non-overlapping work to different processes. However, you might search to see whether someone has written a locking library, or have a go at it yourself: https://en.wikipedia.org/wiki/Mutual_exclusion