ipython并行加载平衡视图随机失败

Question

我的代码是：

from IPython.parallel import Client
from sklearn.datasets import load_digits

def mytask(data, labels, id):
   # ...
   pass

engines = Client()
bview = engines.load_balanced_view()
bview.block = False

digits = load_digits()
X, y = digits.data, digits.target

job = bview.apply(mytask, X, y, 1)

while not job.ready(): # line 242
    time.sleep(2)

print job.result

偶尔在相同的输入下，我的代码会失败：

^{pr2}$

这似乎与我的代码无关。我不知道怎么了。在