When installing tensorflow, execute the command

$ pip install https://storage.googleapis.com/tensorflow/mac/tensorflow-0.5.0-py2-none-any.whl

Reference:
1 http://www.tensorfly.cn/tfdoc/get_ started/os_ setup.html

The error is as follows:

Matplotlib 1.3.1 requirements nose, which is not installed.
Matplotlib 1.3.1 requirements tornado, which is not installed.
installing collected packages: numpy, six, tensorflow
found existing installation: numpy 1.8.0rc1
to solve the problem, the implementation is as follows:

  sudo easy_install nose
  sudo easy_install tornado