矩阵纵横描述

Question

我正在尝试用矩阵来表示。

我现在有的是：

但我想要这个。

使用 tikz 的解决方案可能会更好。

    \documentclass[12pt,a4paper]{article}
    \usepackage[utf8]{inputenc}
    \usepackage{amsmath}
    \usepackage{amsfonts}
    \usepackage{amssymb}
    \usepackage{makeidx}
    \usepackage[left=1.00cm, right=1.00cm]{geometry}

\begin{document}
    \begin{equation}
    \left(
    \begin{array}{*6{c}}
    x_1^{(1)} & x_1^{(2)}  & \cdots & x_1^{(i)}  & \cdots & x_1^{(p)}\\\\
    \vdots & \vdots  & \vdots & \vdots & \vdots & \vdots\\\\
    x_k^{(1)} & x_k^{(2)}  & \cdots & x_k^{(i)}  & \cdots & x_k^{(p)}\\\\
    \vdots & \vdots  & \vdots & \vdots & \vdots & \vdots\\\\
    x_n^{(1)} & x_n^{(2)}  & \cdots & x_n^{(i)}  & \cdots & x_n^{(p)}\\
    \end{array}
    \right) \leftarrow \text{Text} \\
    \end{equation}

\end{document}

Answer 1

通过使用 tikz 进行“绘图”：

\documentclass[12pt,a4paper]{article}
\usepackage[hmargin=1cm]{geometry}
\usepackage[utf8]{inputenc}
\usepackage{amsmath, amssymb}
\usepackage{tikz}
\usetikzlibrary{arrows.meta, matrix, positioning}

\begin{document}
    \begin{equation}
    \begin{tikzpicture}[baseline,
          node distance=1em,
every pin/.append style={pin edge={Straight Barb-,semithick, black},
                         pin distance=9mm, align=left}
                        ]
\matrix (m) [matrix of math nodes,
             column sep=1ex,
             row sep=1ex,
             left  delimiter=(,
             right delimiter=),
             inner sep=1pt
             ]
{
x_1^{(1)} & x_1^{(2)}  & \cdots & x_1^{(i)}  & \cdots & x_1^{(p)}\\
\vdots & \vdots  & \vdots & \vdots & \vdots & \vdots\\
x_k^{(1)} & x_k^{(2)}  & \cdots & x_k^{(i)}  & \cdots & x_k^{(p)}\\
\vdots & \vdots  & \vdots & \vdots & \vdots & \vdots\\
x_n^{(1)} & x_n^{(2)}  & \cdots & x_n^{(i)}  & \cdots & x_n^{(p)}\\
};
\coordinate [pin=right:text,right=of m.east] (aux);
\coordinate [pin=below:text,below=of m-4-4.south |- m.south] {};
    \end{tikzpicture}
    \end{equation}

\end{document}

Answer 2

像这样？我只是用了堆栈。

    \documentclass[12pt,a4paper]{article}
    \usepackage[utf8]{inputenc}
    \usepackage{mathtools}
    \usepackage{amsfonts}
    \usepackage{amssymb}
    \usepackage{makeidx}
    \usepackage[left=1.00cm, right=1.00cm]{geometry}
\usepackage{stackengine}
\stackMath
\def\QQ{\phantom{x_1^{(1)}}}
\begin{document}
    \begin{equation}
    \stackunder{
    \left(
    \begin{array}{*6{c}}
    x_1^{(1)} & x_1^{(2)}  & \cdots & x_1^{(i)}  & \cdots & x_1^{(p)}\\\\
    \vdots & \vdots  & \vdots & \vdots & \vdots & \vdots\\\\
    x_k^{(1)} & x_k^{(2)}  & \cdots & x_k^{(i)}  & \cdots & x_k^{(p)}\\\\
    \vdots & \vdots  & \vdots & \vdots & \vdots & \vdots\\\\
    x_n^{(1)} & x_n^{(2)}  & \cdots & x_n^{(i)}  & \cdots & x_n^{(p)}\\
    \end{array}
    \right) 
    }{
  \begin{array}{*6{c}}
    \QQ&\QQ&\QQ&\stackunder{\uparrow}{\mathclap{\text{Text goes here}}}&\QQ&\QQ
  \end{array}}
     \leftarrow \text{Text} \\
    \end{equation}
\end{document}