eigen3 /usr/include/eigen3/Eigen/Core:42:14: fatal error: math_functions.hpp: No such file or direct

3.3.4 error setup 3.3.8 

一、卸载
1.查看当前版本

pkg-config --modversion eigen3

2.删除eigen3相关文件

sudo rm -rf /usr/include/eigen3
sudo rm -rf /usr/lib/cmake/eigen3
sudo rm -rf /usr/local/include/eigen3
sudo rm -rf /usr/share/doc/libeigen3-dev 
sudo rm -rf /usr/local/share/pkgconfig/eigen3.pc /usr/share/pkgconfig/eigen3.pc /var/lib/dpkg/info/libeigen3-dev.list /var/lib/dpkg/info/libeigen3-dev.md5sums
sudo rm -rf /usr/local/lib/pkgconfig/eigen3.pc
sudo rm -rf /usr/local/share/eigen3

二、安装需要的版本
1.官网下载需要的版本的压缩包解压Releases · libeigen / eigen · GitLab
2.编译安装
这里以3.2.1版本为例

cd eigen-3.2.1
mkdir build
cd build
cmake..
sudo make install
sudo cp -r /usr/local/include/eigen3 /usr/include 

3.查看当前版本

pkg-config --modversion eigen3