使用pip安装Matplotlib时出现内存错误

Question 1

我正在使用Python 2.7，如果我尝试安装Matplotlib，如果我使用“ pip install matplotlib”，则会收到此错误

 Exception:
  Traceback (most recent call last):
    File "/usr/local/lib/python2.7/dist-packages/pip/basecommand.py", line 232, in main
      status = self.run(options, args)
    File "/usr/local/lib/python2.7/dist-packages/pip/commands/install.py", line 339, in run
      requirement_set.prepare_files(finder)
    File "/usr/local/lib/python2.7/dist-packages/pip/req/req_set.py", line 355, in prepare_files
      do_download, session=self.session,
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 782, in unpack_url
      session,
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 667, in unpack_http_url
      from_path, content_type = _download_http_url(link, session, temp_dir)
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 843, in _download_http_url
      _download_url(resp, link, content_file)
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 615, in _download_url
      for chunk in progress_indicator(resp_read(4096), 4096):
    File "/usr/local/lib/python2.7/dist-packages/pip/utils/ui.py", line 46, in iter
      for x in it:
    File "/usr/local/lib/python2.7/dist-packages/pip/download.py", line 580, in resp_read
      decode_content=False):
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/packages/urllib3/response.py", line 256, in stream
      data = self.read(amt=amt, decode_content=decode_content)
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/requests/packages/urllib3/response.py", line 186, in read
      data = self._fp.read(amt)
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/filewrapper.py", line 54, in read
      self.__callback(self.__buf.getvalue())
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/controller.py", line 205, in cache_response
      self.serializer.dumps(request, response, body=body),
    File "/usr/local/lib/python2.7/dist-packages/pip/_vendor/cachecontrol/serialize.py", line 81, in dumps
      ).encode("utf8"),
  MemoryError"

可能是什么问题？我正在将树莓派2与16gb SD卡一起使用。我仍然有8gb的可用数据，但仍然收到此错误。请帮助

Question 2

出现此错误的原因是，似乎pip的缓存机制正在尝试在将整个文件缓存之前将其读取到内存中……这在有限的内存环境中造成了问题，因为matplotlib约为50mb。

一个简单的办法，直到PIP进行了修补，使用恒定的空间缓存算法，是运行pip与--no-cache-dir避免缓存：

$ pip --no-cache-dir install matplotlib

Question 3

看来您没有足够的RAM从头开始构建matplotlib。为了克服这个问题，可以打开交换：

# create swap file of 512 MB
dd if=/dev/zero of=/swapfile bs=1024 count=524288
# modify permissions
chown root:root /swapfile
chmod 0600 /swapfile
# setup swap area
mkswap /swapfile
# turn swap on
swapon /swapfile

或者，如果在SD卡上安装了raspbian，则可以从存储库中安装matplotlib：

apt-get install python-matplotlib

Question 4

--no-cache-dir没有为我工作。我刚刚关闭了所有应用程序，然后才能够完成安装。