我包装了一些可能会用try / except块耗尽内存的代码。但是，尽管会生成MemoryError，但不会捕获该错误。

我有以下代码：

    while True:
        try:
            self.create_indexed_vocab( vocab )
            self.reset_weights()
            break;
        except MemoryError:
            # Stuff to reduce size of vocabulary
            self.vocab, self.index2word = None, None
            self.syn0, self.syn1 = None, None

            self.min_count += 1
            logger.info( ...format string here... )

我得到以下回溯：

File "./make_model_tagged_wmt11.py", line 39, in <module>
  model.build_vocab(sentences)
File "/root/CustomCompiledSoftware/gensim/gensim/models/word2vec.py", line 236, in build_vocab
  self.reset_weights()
File "/root/CustomCompiledSoftware/gensim/gensim/models/word2vec.py", line 347, in reset_weights
  self.syn0 += (random.rand(len(self.vocab), self.layer1_size) - 0.5) / self.layer1_size
File "mtrand.pyx", line 1044, in mtrand.RandomState.rand (numpy/random/mtrand/mtrand.c:6523)
File "mtrand.pyx", line 760, in mtrand.RandomState.random_sample (numpy/random/mtrand/mtrand.c:5713)
File "mtrand.pyx", line 137, in mtrand.cont0_array (numpy/random/mtrand/mtrand.c:1300)
MemoryError

我在Ubuntu 12.04下运行Python 2.7.3

该reset_weights行self.syn0恰好是我期望引发异常的行（它分配了一个大数组）。令人费解的是，我无法捕获内存错误，无法执行使数组大小变小的操作。

是否有特殊情况导致MemoryError无法被抓住？