解决问题
ImportError: Could not find 'cudart64_90.dll'. TensorFlow requires that this DLL be installed in a directory that is named in your %PATH% environment variable. Download and install CUDA 9.0 from this URL: https://developer.nvidia.com/cuda-toolkit
解决思路
导入错误：找不到“cudart64_90.dll”。TensorFlow要求将此dll安装在%Path%环境变量中命名的目录中。从以下网址下载并安装CUDA 9.0:https://developer.nvidia.com/cuda-toolkit
解决方法
缺少dll文件，有两种情况
T1、重新安装Cuda及Cudnn
参考文章：TF学习——TF安装(Cuda/Cudnn)：Win10下安装深度学习框架Tensorflow+Cuda+Cudnn最简单最快捷最详细攻略(图文教程)
T2、安装tensorflow
pip install tensorflow-gpu==1.4.0
