矩阵和 TikZ：矩阵内的箭头

Question

在下面的例子中，箭头适合矩阵内部，但我希望它们停止在分隔符的边界处。

    \documentclass[border=5pt]{standalone}
    \usepackage{tikz}
    \usetikzlibrary{matrix,decorations.pathreplacing, calc, positioning,fit}
    \begin{document}

    \begin{tikzpicture}[>=stealth,thick,baseline]
    \matrix [matrix of math nodes,left delimiter=(,right delimiter=)](A){ 
    a_{1,1} & a_{1,2} & \dots  & a_{1,j} & \dots & a_{1,n}\\
    a_{2,1} & a_{2,2} & \dots  & a_{2,j} & \dots & a_{2,n}\\  
    \vdots  & \vdots  &  & \vdots  &  & \vdots\\
    a_{i,1} & a_{i,2} & \dots  & a_{i,j} & \dots & a_{i,n}\\
    \vdots  & \vdots  &  & \vdots  &  & \vdots\\
    a_{n,1} & a_{n,2} & \dots  & a_{n,j} & \dots & a_{n,n}\\
   };

   \node[
     fit=(A-4-6)(A-4-6),
     inner xsep=20pt,inner ysep=0,
     label=right: $i$-ième ligne
    ](L) {};

   \node[
     fit=(A-6-4)(A-6-4),
     inner xsep=20pt,inner ysep=20pt,
     label=below: $j$-ième colonne
     ](C) {};

    \draw[->](L.east)-- (A-4-6);
    \draw[->](C.south)-- (A-6-4);

    \end{tikzpicture}

    \end{document}

Answer 1

添加xshift：

 \documentclass[border=5pt]{standalone}
    \usepackage{tikz}
    \usetikzlibrary{matrix,decorations.pathreplacing, calc, positioning,fit}
    \begin{document}

    \begin{tikzpicture}[>=stealth,thick,baseline]
    \matrix [matrix of math nodes,left delimiter=(,right delimiter=)](A){ 
    a_{1,1} & a_{1,2} & \dots  & a_{1,j} & \dots & a_{1,n}\\
    a_{2,1} & a_{2,2} & \dots  & a_{2,j} & \dots & a_{2,n}\\  
    \vdots  & \vdots  &  & \vdots  &  & \vdots\\
    a_{i,1} & a_{i,2} & \dots  & a_{i,j} & \dots & a_{i,n}\\
    \vdots  & \vdots  &  & \vdots  &  & \vdots\\
    a_{n,1} & a_{n,2} & \dots  & a_{n,j} & \dots & a_{n,n}\\
   };

   \node[
     fit=(A-4-6)(A-4-6),
     inner xsep=20pt,inner ysep=0,
     label=right: $i$-ième ligne
    ](L) {};

   \node[
     fit=(A-6-4)(A-6-4),
     inner xsep=20pt,inner ysep=20pt,
     label=below: $j$-ième colonne
     ](C) {};

    \draw[->](L.east)-- ([xshift=12pt]A-4-6.east);
    \draw[->](C.south)-- (A-6-4);

    \end{tikzpicture}

    \end{document}

或者缩短箭头：

 \documentclass[border=5pt]{standalone}
    \usepackage{tikz}
    \usetikzlibrary{matrix,decorations.pathreplacing, calc, positioning,fit}
    \begin{document}

    \begin{tikzpicture}[>=stealth,thick,baseline]
    \matrix [matrix of math nodes,left delimiter=(,right delimiter=)](A){ 
    a_{1,1} & a_{1,2} & \dots  & a_{1,j} & \dots & a_{1,n}\\
    a_{2,1} & a_{2,2} & \dots  & a_{2,j} & \dots & a_{2,n}\\  
    \vdots  & \vdots  &  & \vdots  &  & \vdots\\
    a_{i,1} & a_{i,2} & \dots  & a_{i,j} & \dots & a_{i,n}\\
    \vdots  & \vdots  &  & \vdots  &  & \vdots\\
    a_{n,1} & a_{n,2} & \dots  & a_{n,j} & \dots & a_{n,n}\\
   };

   \node[
     fit=(A-4-6)(A-4-6),
     inner xsep=20pt,inner ysep=0,
     label=right: $i$-ième ligne
    ](L) {};

   \node[
     fit=(A-6-4)(A-6-4),
     inner xsep=20pt,inner ysep=20pt,
     label=below: $j$-ième colonne
     ](C) {};

    \draw[->, shorten > =12pt](L.east)-- (A-4-6.east);
    \draw[->](C.south)-- (A-6-4);

    \end{tikzpicture}

    \end{document}

顺便问一下你为什么需要fit？

\documentclass[border=5pt]{standalone}
\usepackage{tikz}
    \usetikzlibrary{matrix, positioning}

    \begin{document}

    \begin{tikzpicture}[>=stealth,thick,baseline]
    \matrix [matrix of math nodes,left delimiter=(,right delimiter=)](A){ 
    a_{1,1} & a_{1,2} & \dots  & a_{1,j} & \dots & a_{1,n}\\
    a_{2,1} & a_{2,2} & \dots  & a_{2,j} & \dots & a_{2,n}\\  
    \vdots  & \vdots  &  & \vdots  &  & \vdots\\
    a_{i,1} & a_{i,2} & \dots  & a_{i,j} & \dots & a_{i,n}\\
    \vdots  & \vdots  &  & \vdots  &  & \vdots\\
    a_{n,1} & a_{n,2} & \dots  & a_{n,j} & \dots & a_{n,n}\\
   };

   \node[right =30pt of A-4-6.east](L)  {$i$-ième ligne};

   \node[below=20pt of A-6-4.south](C) {$j$-ième colonne};

    \draw[->, shorten > =12pt](L.west)-- (A-4-6.east);
    \draw[->](C.north)-- (A-6-4.south);

    \end{tikzpicture}

    \end{document}

Answer 2

矩阵分隔符nodes默认未命名。因此，如果您添加名称，则可以像任何其他节点一样使用它们作为参考，并且线条将在其边界上停止。

在下面的代码中，我使用every right delimiter样式添加了稍后会使用的名称。

矩阵是一种特殊的节点，它包含其他节点。因此，如果您想在matrix边界上停止一条线，可以使用矩阵名称作为参考。矩阵元素有自己的边界。我使用列中心和南矩阵边界之间的交点来放置垂直箭头，使用行中心和右分隔符上的东锚来放置水平箭头。如果您需要理解-|（或|-）语法，请查看https://tex.stackexchange.com/a/481234/1952或者https://tex.stackexchange.com/a/22954/1952。

\documentclass[border=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{matrix,decorations.pathreplacing, calc, positioning,fit}
\begin{document}

\begin{tikzpicture}[>=stealth,thick,baseline,
every right delimiter/.append style={name=rd},
]
\matrix [matrix of math nodes, 
    left delimiter=(, 
    right delimiter=),
    ](A){ 
a_{1,1} & a_{1,2} & \dots  & a_{1,j} & \dots & a_{1,n}\\
a_{2,1} & a_{2,2} & \dots  & a_{2,j} & \dots & a_{2,n}\\  
\vdots  & \vdots  &  & \vdots  &  & \vdots\\
a_{i,1} & a_{i,2} & \dots  & a_{i,j} & \dots & a_{i,n}\\
\vdots  & \vdots  &  & \vdots  &  & \vdots\\
a_{n,1} & a_{n,2} & \dots  & a_{n,j} & \dots & a_{n,n}\\
};

\draw[<-] (rd.east|-A-4-1.center)--++(0:6mm) node[right]{$i$-ième colonne};
\draw[<-] (A.south-|A-1-4.center) --++(-90:6mm) node[below]{$j$-ième colonne};

\end{tikzpicture}

\end{document}