我有很多独立的任务,读取但不写入相同的gensim模型,大小约为3.6GB。 (Gensim是一个基于numpy的主题建模库。)所以我决定通过首先从文件加载gensim模型来并行化它们:
from gensim.models.word2vec import Word2Vec
from multiprocessing import Pool
model = Word2Vec.load_word2vec_format('GoogleNews-vectors-negative300.bin', binary=True)
然后将model
作为参数传递给要运行doWork
的进程池:
def doWork(experiment, doc):
print "Begin working"
# do some work here; access model by experiment.model
class Experiment(object):
def __init__(self, model, docs):
self.model = model
self.docs = docs
def run(self):
pool = Pool(processes = 4)
print "Done preparing"
results = pool.map(doWork, [(self, doc) for doc in self.docs])
return results
experiment = Experiment(model, ['doc1.txt', 'doc2.txt'])
experiment.run()
当我运行此脚本时(我在此处显示的两个段是可运行的脚本;请复制),它卡在pool.map
行并且发生了SystemError
。输出是:
Done preparing
Exception in thread Thread-2:
Traceback (most recent call last):
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 810, in __bootstrap_inner
self.run()
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 763, in run
self.__target(*self.__args, **self.__kwargs)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/pool.py", line 342, in _handle_tasks
put(task)
SystemError: NULL result without error in PyObject_Call
在将gensim引入我的程序之前,从未发生过该错误。 (没有多处理的Gensim也适用于我。)我认为它可能与基础gensim和numpy(BLAS)的C代码的互操作有关。 我想知道这个错误的原因以及如何修复它。如果我不能将gensim用于子处理,还有什么替代方案?
我认为model
不会被复制,因为我的操作系统(Mac OS X)应该使用写时复制策略。我不认为它与内存同步有关,因为没有打印一行“开始工作”,即我的代码没有访问model
。错误在于将model
传递给子流程。