Segmentation fault when using Arpack and Threads.@threads

[CodeLenz]

Hi.

The following example

 function test_call_parpack(NP,NM)

    # Parallel calls to Arpack
    Threads.@threads for k=1:NP

        # Generate random matrix
        A = sprand(NM,NM,0.2)

        # Call Arpack
        eigs(A)

    end

end

results in

julia> test_call_parpack(1000,1000)
Segmentation fault (core dumped)

If I run the sequence 

# Generate random matrix
    A = sprand(NM,NM,0.2)

    # Call Arpack
    eigs(A)

by hand many times, everything works fine. I suspect there must be some constraint on using external libraries in parallel, but all the variables are local to the loop and Julia just have to call multiple instances of it. Is it expected?

Julia 1.3 here Thanks for your assistance.

[andreasnoack]

See https://stackoverflow.com/a/6972455. Arpack might not be threadsafe. Consider using a native Julia implementation such as e.g. https://github.com/haampie/ArnoldiMethod.jl

[CodeLenz]

Thanks!