首先我们要从源码克隆caffe2的库：
git clone --recursive https://github.com/caffe2/caffe2.git
执行下载过程会报这样的错：
Cloning into 'third_party/eigen'... fatal: could not read Username for 'https://github.com': No such device or address fatal: clone of 'https://github.com/RLovelett/eigen.git' into submodule path 'third_party/eigen' failed
这是因为这个github网址找不到，打开网页，果然404.
解决方法如下：
cd third_party git clone https://github.com/eigenteam/eigen-git-mirror mv eigen-git-mirro eigen cd .. git submodule update --init --recursive
继续上次报错点继续下载
然后你会发现又报了一个错：
Submodule path 'third_party/zstd': checked out 'aec56a52fbab207fc639a1937d1e708a282edca8' Unable to checkout 'f3c627d517968c20e8269ead1d90cd3a6c199356' in submodule path 'third_party/aten'
因为到目前为止，facebook已将caffe2集成在pytorch里，https://github.com/pytorch/pytorch
根据安装教程链接
conda install -c caffe2 caffe2-cuda9.0-cudnn7
安装成功