[SO] Multiple selection from Julia array

test.jl

function foo(genconv, I, J)
    genconv[sub2ind(size(genconv),I,J)]
end
function bar(genconv, I, J)
    diag(sub(genconv, I, J))
end
function baz(genconv, I, J)
    [genconv[i,j] for (i,j) in zip(I, J)]
end

function benchmark()
    genconv = rand(10000, 20000)
    I = rand(collect(1:size(genconv)[1]), 10000)
    J = rand(collect(1:size(genconv)[2]), 10000)
    # warmup
    foo(genconv, I, J)
    bar(genconv, I, J)
    baz(genconv, I, J)

    println("foo:")
    @time foo(genconv, I, J)
    println("bar:")
    @time bar(genconv, I, J)
    println("baz:")
    @time baz(genconv, I, J)
    return "finished"
end

benchmark()

julia> benchmark()
foo:
  0.000447 seconds (7 allocations: 156.438 KB)
bar:
  0.000904 seconds (25 allocations: 157.078 KB)
baz:
  0.000368 seconds (3 allocations: 78.219 KB)