如何绘制这个矩阵

Question

您知道如何绘制附加矩阵吗？

Answer 1

这是一个带有的命题nicematrix。

\documentclass{article}
\usepackage{nicematrix,tikz}

\begin{document}

\NiceMatrixOptions
  {
    xdots = 
     {
       color = gray ,
       shorten = 3pt ,
       horizontal-labels  % with nicematrix ≥ 6.20 
     }
  }

$\begin{pNiceMatrix}[columns-width=8mm,first-row,first-col]
& \Hdotsfor[line-style={solid,<->},color=black]{4}^{d_u} \\
\Vdotsfor[line-style={solid,<->},color=black]{4}_{d_1}
& a_{11} & a_{12} & \Cdots & a_{1d_u} & 0 & \Cdots & & 0 \\[1.5mm]
& a_{21} & a_{22} &  &         &   & &   & \Vdots \\[1.5mm]
& \Vdots &  & \Ddots &        &    & \Ddots  &  \Ddots &   \\[1.5mm]
& a_{d_11}&  &    &        &    &   &   & 0 \\[1.5mm]
& 0      &  \Ddots[shorten-end=-5mm] &    &        &    &   &   & a_{n-d_u+1,n}  \\[1.5mm]
& \Vdots & \Ddots &    &        &    &   &   &   \\[1.5mm]
&       &  &    &        &    &   &   &  \Vdots \\[1.5mm]
& 0  & \Cdots &    & 0 & a_{n,n-d_1+1}   & \Cdots  &   &  a_{nn}\\
\end{pNiceMatrix}$

\end{document}