一运行ivreghdfe就报错，或是加上absorb就运行不了可以重新安装ivreghdfe用到的工具，个人认为可能是版本的问题不兼容
以下命令为安装代码，直接在stata中输入help ivreghdfe可以得出来，如果选中四条命令运行不了可以先运行一部分比如安装reghdfe或ivreg2再重新运行这四条命令
*Install ftools (remove program if it existed previously)
cap ado uninstall ftools
net install ftools, from("https://raw.githubusercontent.com/sergiocorreia/ftools/master/src/")

* Install reghdfe
cap ado uninstall reghdfe
net install reghdfe, from("https://raw.githubusercontent.com/sergiocorreia/reghdfe/master/src/")

* Install ivreg2, the core package
cap ado uninstall ivreg2
ssc install ivreg2

* Finally, install this package
cap ado uninstall ivreghdfe
net install ivreghdfe, from(https://raw.githubusercontent.com/sergiocorreia/ivreghdfe/master/src/)