问题
我正在尝试在虚拟环境中使用scikit学习，但我无法让它运行。
例如，我转到一个项目文件夹，安装NumPy、SciPy和scikit学习
virtualenv venv
source venv/bin/activate
pip install numpy
pip install scipy
pip install scikit-learn
然后我打开python并尝试导入它们中的每一个。
import numpy
import scipy
import sklearn
NumPy和SciPy导入很好，但当我尝试导入时，我收到一个错误，说Library not loaded: @rpath/./libgfortran.3.dylib。
我在安装过程中遗漏了什么吗？
完整错误消息：
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/sklearn/__init__.py", line 57, in <module>
from .base import clone
File "/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/sklearn/base.py", line 11, in <module>
from .utils.fixes import signature
File "/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/sklearn/utils/__init__.py", line 11, in <module>
from .validation import (as_float_array,
File "/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/sklearn/utils/validation.py", line 16, in <module>
from ..utils.fixes import signature
File "/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/sklearn/utils/fixes.py", line 324, in <module>
from scipy.sparse.linalg import lsqr as sparse_lsqr
File "/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/scipy/sparse/linalg/__init__.py", line 109, in <module>
from .isolve import *
File "/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/scipy/sparse/linalg/isolve/__init__.py", line 6, in <module>
from .iterative import *
File "/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/scipy/sparse/linalg/isolve/iterative.py", line 7, in <module>
from . import _iterative
ImportError: dlopen(/Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/scipy/sparse/linalg/isolve/_iterative.so, 2): Library not loaded: @rpath/./libgfortran.3.dylib
Referenced from: /Users/Peter/git/dataSandbox/flaskApps/sfSalary/venv/lib/python2.7/site-packages/scipy/sparse/linalg/isolve/_iterative.so
Reason: image not found
编辑：这是使用sklearn托管Heroku应用程序的一些疑难解答。
我强烈建议不要使用NumPy/SciPy/Scikit学习的虚拟环境和其他包含编译代码的包。虚拟环境可以很好地处理纯Python依赖项，但对于在Python之外具有依赖项的已编译扩展，它们可能会以意想不到的方式失败（正如您所看到的）。
如果你想用不同版本的Python包（包括编译的扩展）管理多个环境，最好的工具可能是conda，尤其是conda环境。
有了它，你可以运行以下程序：
$ conda create -n myenv python=3.4 numpy scipy scikit-learn
$ source activate myenv
(myenv) $ python
Python 3.4.3
>>> import sklearn
你就可以走了。