Tensorflow C++ 学习（一） 搭建环境

前言

Tensorflow 网上大部分是python的资料较多，而C++方面的极少，因此，接下来会有一系列的博客用于学习tensorflow,记录学习的过程。加油！

搭建环境

既然使用C++的API，那第一步就是搭建Tensorflow的工作环境
1. 准备一台64位的虚拟机 ，我安装的ubuntu 16.04 64位的. 用新的虚拟机主要是图个干净利落，同时修改好软件源，建议改成阿里云的，安装一些常用的运行库，开发库。
2. 安装 bazel

> echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel.list
curl https://bazel.build/bazel-release.pub.gpg | sudo apt-key add -
>sudo apt-get update && sudo apt-get install bazel

可能会提示没有安装curl，则需要先安装curl

> sudo apt-get install curl

安装bazel

>sudo apt-get update && sudo apt-get install bazel

本人使用 ubuntu 16.04刚上的虚拟机，妥妥的。
3. 安装python的一些常用库

>sudo apt-get install sudo apt-get install python-numpy python-dev python-pip python-wheel -y

1. 安装cpu 开发工具库

>sudo apt-get install libcupti-dev

1. 下载tensorflow 源码

>sudo apt-get install git 
>git clone https://github.com/tensorflow/tensorflow
>cd tensorflow
>./configure #这一步不可少！否则后面c++编译不过

出现这个就配置对了：

INFO:All external dependencies fetched successfully.

1. 安装tensorflow ，使用pip

>pip install --upgrade tensorflow

1. 测试C++接口

将 tensorflow目录下的：tensorflow/cc/example/example.cc 文件内容替换为（没有就新建一个这个目录下的文件）:

// tensorflow/cc/example/example.cc

#include "tensorflow/cc/client/client_session.h"
#include "tensorflow/cc/ops/standard_ops.h"
#include "tensorflow/core/framework/tensor.h"

int main() {
using namespace tensorflow;
using namespace tensorflow::ops;
  Scope root = Scope::NewRootScope();
// Matrix A = [3 2; -1 0]
auto A = Const(root, { {3.f, 2.f}, {-1.f, 0.f}});
// Vector b = [3 5]
auto b = Const(root, { {3.f, 5.f}});
// v = Ab^T
auto v = MatMul(root.WithOpName("v"), A, b, MatMul::TransposeB(true));
std::vector<Tensor> outputs;
  ClientSession session(root);
// Run and fetch v
  TF_CHECK_OK(session.Run({v}, &outputs));
// Expect outputs[0] == [19; -3]
std::cout<< outputs[0].matrix<float>();
return 0;
}

在tensorflow/cc/example/ 目录下新建一个BUILD文件，文件内容：

cc_binary(
 name = "example",
 srcs = ["example.cc"],
 deps = [
"//tensorflow/cc:cc_ops",
"//tensorflow/cc:client_session",
"//tensorflow/core:tensorflow",
 ],
)

编译：

>cd tensorflow #回到tensorflow的主目录下
>bazel run -c opt //tensorflow/cc/example:example

然后首次编译很久，等一会儿就好。

最后打印出：

2017-06-13 17:20:50.578854: W tensorflow/core/platform/cpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use SSE4.1 instructions, but these are available on your machine and could speed up CPU computations.
2017-06-13 17:20:50.578970: 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.
2017-06-13 17:20:50.578992: 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.
19
-3

说明安装成功。
但是！这里有太多的调试信息了，我们把它去掉：

>export TF_CPP_MIN_LOG_LEVEL=2 
>bazel-bin/tensorflow/cc/example/example

打印：

19
-3

OK Perfect!