TensorFlow入门：mac 安装 TensorFlow
开发环境：
mac os 10.12.5
Python 2.7.10
GCC 4.2.1
mac默认是不带pip的，安装pip。
sudo easy_install pip
1.安装virtualenv
sudo pip install virtualenv --upgrade
创建一个工作目录：
sudo virtualenv --system-site-packages ~/tensorflow
进行该目录，激活沙箱
cd ~/tensorflow
source bin/activate
2.virtualenv里安装TensorFlow
进入沙箱后，执行下面的命令来安装TensorFlow:
(tensorflow)$ sudo pip install tensorflow==1.2.1
3.运行TensorFlow
...
environment /Users/***/tensorflow
Successfully installed backports.weakref-1.0rc1 bleach-1.5.0 funcsigs-1.0.2 html5lib-0.9999999 markdown-2.6.8 mock-2.0.0 numpy-1.13.0 pbr-3.1.1 protobuf-3.3.0 six-1.10.0 tensorflow-1.2.1 werkzeug-0.12.
hello world测试一下：
$ python
Python 2.7.10 (default, Feb 7 2017, 00:08:15)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.34)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> import tensorflow as tf
>>> hello =tf.constant(‘hello world!‘)
>>> sess = tf.Session()
2017-07-05 23:58:34.771619: W tensorflow/core/platform/cpu_feature_guard.cc:45] The TensorFlow library wasn‘t compiled to use SSE4.2 instructions, but these are available on your machine and could speed up CPU computations.
2017-07-05 23:58:34.771654: W tensorflow/core/platform/cpu_feature_guard.cc:45] The TensorFlow library wasn‘t compiled to use AVX instructions, but these are available on your machine and could speed up CPU computations.
2017-07-05 23:58:34.771663: W tensorflow/core/platform/cpu_feature_guard.cc:45] The TensorFlow library wasn‘t compiled to use AVX2 instructions, but these are available on your machine and could speed up CPU computations.
2017-07-05 23:58:34.771671: W tensorflow/core/platform/cpu_feature_guard.cc:45] The TensorFlow library wasn‘t compiled to use FMA instructions, but these are available on your machine and could speed up CPU computations.
>>> print sess.run(hello)
hello world!
恭喜，TensorFlow安装成功了。
*每次运行TensorFlow程序时，都需要进入tensorflow目录，然后执行source bin/activate 命令来激活沙箱。
*Ubuntu/Linux也可以按Mac os准备。TensorFlow安装版本分为CPU版和GPU版，区别在于：
(tensorflow)$ sudo pip install tensorflow==1.2.1
(tensorflow)$ sudo pip install tensorflow-gpu==1.2.1