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multithreadingjulia
crevell
crevell

Reputation: 460

Julia @threads single

Is there something in Julia Threads similar to a single command in OpenMP that will ensure all threads wait before a particular block of code and then execute that block in only one thread? I have a loop that distributes calculations of forces between threads before performing an update to all locations at once, and I cannot find any feature to achieve this without terminating the @threads loop.

Upvotes: 2

Views: 950

Answers (1)

Przemyslaw Szufel
Przemyslaw Szufel

Reputation: 42244

You can use locks:

function f()
    l = Threads.SpinLock()
    x = 0
    Threads.@threads for i in 1:10^7
        Threads.lock(l)
        x += 1  # this block is executed only in one thread
        Threads.unlock(l)
    end
    return x
end

Note that the SpinLock mechanism is dedicated to non-blocking codes (that is computations only, no I/O in the loop). If there is I/O involved ReentrantLock should be used instead.

Upvotes: 5

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