出现导入错误：安装 auto-sklearn 时没有名为“sklearn”的模块

为什么我得到ImportError: No module named 'sklearn'安装时auto-sklearn通过点？

$ virtualenv -p python3 automl
$ cd automl/
$ source bin/activate
$ pip install auto-sklearn
Collecting auto-sklearn
  Downloading auto-sklearn-0.1.1.tar.gz (5.9MB)
    100% |████████████████████████████████| 5.9MB 265kB/s 
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-whq6xjt6/auto-sklearn/setup.py", line 2, in     <module>
        import autosklearn
      File "/tmp/pip-build-whq6xjt6/auto-sklearn/autosklearn/__init__.py", line 2, in <module>
        from autosklearn.util import dependencies
      File "/tmp/pip-build-whq6xjt6/auto-sklearn/autosklearn/util/__init__.py", line 4, in <module>
        from .common import *
      File "/tmp/pip-build-whq6xjt6/auto-sklearn/autosklearn/util/common.py", line 4, in <module>
        from sklearn.externals import six
    ImportError: No module named 'sklearn'

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-whq6xjt6/auto-sklearn/

pip 发行版中似乎缺少依赖项。但是为什么自动安装依赖不起作用呢？我可以这样安装 auto-sklearn：

$ wget https://raw.githubusercontent.com/automl/auto-sklearn/master/requirements.txt
$ pip install -r requirements.txt
$ pip install numpy six Cython      # something goes wrong here too!?
$ pip install -r requirements.txt
$ pip install auto-sklearn

我查看了 tar.gz tar 文件https://pypi.python.org/pypi/auto-sklearn/0.1.1 https://pypi.python.org/pypi/auto-sklearn/0.1.1和install_requires in setup.py对我来说似乎没问题。是否MANIFEST.in需要一个requirements.txt line?

我为此在 GitHub 上提出了一个问题：https://github.com/automl/auto-sklearn/issues/206 https://github.com/automl/auto-sklearn/issues/206但那已被关闭。需要手动安装的原因是什么？