在Ubuntu上安装OpenBLAS和Eigen

安装 openblas

直接使用 apt-get 命令即可安装：

sudo apt-get install libopenblas-dev

检查是否安装成功，可以用下面的示例代码 example.cpp：

#include <stdio.h>
#include <stdlib.h>
#include "cblas.h"int main() {const int n = 10;  // Array sizeconst double da = 10; // Double constantdouble dx[n]; // Input double arraydouble dy[n]; // Output double array// Initialize the arraysfor (int i = 0; i < n; ++i) {dx[i] = 9 - i;dy[i] = i;}// Print the original dy arrayprintf("Original dy: ");for (int i = 0; i < n; ++i) {printf("%f ", dy[i]);}printf("\n");// Perform daxpy operation: dy = da * dx + dycblas_daxpy(n, da, dx, 1, dy, 1);// Print the modified dy arrayprintf("Modified dy: ");for (int i = 0; i < n; ++i) {printf("%f ", dy[i]);}printf("\n");return 0;
}

编译并运行：

~$ gcc example.cpp -lopenblas -o example
~$ ./example
Original dy: 0.000000 1.000000 2.000000 3.000000 4.000000 5.000000 6.000000 7.000000 8.000000 9.000000 
Modified dy: 90.000000 81.000000 72.000000 63.000000 54.000000 45.000000 36.000000 27.000000 18.000000 9.000000

安装 Eigen

Eigen 官网：https://eigen.tuxfamily.org/index.php?title=Main_Page

在官网找一个源码下载，解压后安装：

~$ wget https://gitlab.com/libeigen/eigen/-/archive/3.4.0/eigen-3.4.0.tar.gz
~$ tar -zxvf eigen-3.4.0.tar.gz
~$ mkdir build
~$ cd build
~$ cmake ..
~$ sudo make install

eigen3会被默认安装到 /usr/local/include/eigen3 路径下，需要移动到 /usr/local/include 下面：

~$ sudo mv /usr/local/include/eigen3/* /usr/local/include/

然后把 /usr/local/include/eigen3 删除掉：

~$ sudo rm -rf /usr/local/include/eigen3

最后来跑一下官方示例 my_program.cpp：

#include <iostream>
#include <Eigen/Dense>using Eigen::MatrixXd;int main()
{MatrixXd m(2, 2);m(0, 0) = 3;m(1, 0) = 2.5;m(0, 1) = -1;m(1, 1) = m(1, 0) + m(0, 1);std::cout << m << std::endl;
}

编译运行：

~$ g++ my_program.cpp -o my_program
~$ ./my_program3  -1
2.5 1.5