function ttime(adim)
  r1 = rand(adim, adim)
  @time begin
    summ = 0.0
    for i in 1:adim
      for j in 1:adim
        summ += r1[i,j]
      end
    end
    println(summ)
  end

  @time begin
    summ = 0.0
    for j in 1:adim
      for i in 1:adim
        summ += r1[i,j]
      end
    end
    println(summ)
  end
end

ttime(40) # to precompile
ttime(16000) # to give it a load

# Row-major order really is about 10-12 times slower in Julia