How to check the number of threads
Threads.nthreads()
Output:
8
For me, I have eight threads at my disposal for code execution.
How to check thread id
Threads.threadid()
Output:
1
Since we are on the master thread, Threads.threadid() will return 1.
@threads Macro
Below we create a with 10 elements in it, then use multi-threads to put thread id used to process the given for loop. To use multi-thread, we use Threads.@threads in front of a for loop to indicate the region that follows are multi-threaded region.
a = zeros(10)
Threads.@threads for i = 1:10
a[i] = Threads.threadid()
end
Output:
10-element Vector{Float64}:
1.0
1.0
2.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0