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有向图

tag-icon • tag-icon graphics diagrams xfig
有向图

我的图表对齐有问题，我不知道如何使前两个有向图与“=”对齐，并与左括号（“{”）对齐。我的代码如下

\documentclass[12pt]{report}
\usepackage{tikz} 
\usetikzlibrary{calc}
\begin{document}
\begin{center}

\begin{tikzpicture}[thick]
\node (p0) at ( -2.3,0.25) {};
\node (p1) at ( 0, 0) {}; 
\node (p2) at ( 0.8,-0.2) {$i$};
    \node (p3) at ( 2,0) {};
    \node (p4) at ( 0,0.6) {};
    \node (p5) at ( 1.8,0.8) {$j$};
\node (p6) at ( 2,0.6) {};

\node (p7) at ( 2.2,0.3) {$\cdot$}; 

\node (p8) at ( 2.4,0) {};  
\node (p9) at ( 3.5,-0.2) {$k$};  
\node (p10) at ( 4.4,0) {};  
\node (p11) at ( 2.4,0.6) {};  
\node (p12) at ( 2.8,0.8) {$l$};  
\node (p13) at ( 4.4,0.6) {};  

\node (p14) at (4.6,-0.3){=};

\begin{scope}
   \draw (p1) -- (p3); 
   \draw (p4) -- (p6);
   \draw [ shorten <=-0.08cm, shorten >=-0.15cm, -latex](p2) -- (p5);
   \draw (p8) -- (p10); 
   \draw (p11) -- (p13);
   \draw [ shorten <=-0.08cm, shorten >=-0.15cm, -latex](p9) -- (p12);
\end{scope}
\end{tikzpicture}$
\left\{
\begin{array}{c l}
{
\begin{tikzpicture}[thick]
\node (p1) at ( 0, -1) {}; 
\node (p3) at ( 3,-1) {};
\node (p4) at ( 0,0) {};
\node (p6) at ( 3,0) {};
\node (p7) at ( 0,1) {};
\node (p9) at ( 3,1) {};
\node (p2) at ( 1, -1.2) {$i$};
\node (p5) at ( 2,0) {};
\node (p10)at (2.05,-0.2){};
\node (p8) at ( 1.5,1.2) {$l$};

\node (p11)at (3.3, 0){=};

\node (p12)at (3.6, -0.5){};
\node (p13)at (4.6, -0.7){$i$};
\node (p14)at (6.6, -0.5){};
\node (p15)at (3.6, 0.5){};
\node (p16)at (5.1, 0.7){$l$};
\node (p17)at (6.6, 0.5){};
\node (p18)at (7.5, 0){si j=k};
\begin{scope}
   \draw (p1) -- (p3); 
   \draw (p4) -- (p6);
   \draw (p7) -- (p9);
   \draw [ shorten <=-0.08cm, shorten >=-0.15cm, -latex](p2) -- (p5);
   \draw [ shorten <=0.02cm, shorten >=-0.10cm, -latex](p10) -- (p8);

   \draw (p12) -- (p14); 
   \draw (p15) -- (p17);
   \draw [shorten <=-0.08cm, shorten >=-0.1cm, -latex](p13) -- (p16);
\end{scope}
\end{tikzpicture}
} \\
\\
0,$ \hspace{16mm} en otro caso$\\    
\\

\end{array}
\right.
$
\end{center}
\end{document}

它显示了以下图表：

总之，我想要的是以下内容：（我编辑了上面的图片来绘制所需的图表）

所需图表

答案1

简短的回答是，如果你添加baseline=(current bounding box.center)到你的tikzpicture环境中，那么它们将垂直居中在它们的中点附近，这样你的方程式就应该正确对齐。

在此处输入图片描述

事实上，对于您的示例，这并不完全有效，因为您以一种不寻常的方式排版。首先，显示的方程式应放在环境内equation或内部\[...\]（而不是放在使用 排版的居中方程式内）$...$。其次，像这样具有多个分支的方程式最好使用cases来自数学包。进行这些更改将得到上图，代码如下所示：

\documentclass[12pt]{report}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\[
\begin{tikzpicture}[thick,baseline=(current bounding box.center)]
  \node (p0) at ( -2.3,0.25) {};
  \node (p1) at ( 0, 0) {};
  \node (p2) at ( 0.8,-0.2) {$i$};
      \node (p3) at ( 2,0) {};
      \node (p4) at ( 0,0.6) {};
      \node (p5) at ( 1.8,0.8) {$j$};
  \node (p6) at ( 2,0.6) {};

  \node (p7) at ( 2.2,0.3) {$\cdot$};

  \node (p8) at ( 2.4,0) {};
  \node (p9) at ( 3.5,-0.2) {$k$};
  \node (p10) at ( 4.4,0) {};
  \node (p11) at ( 2.4,0.6) {};
  \node (p12) at ( 2.8,0.8) {$l$};
  \node (p13) at ( 4.4,0.6) {};

  \begin{scope}
     \draw (p1) -- (p3);
     \draw (p4) -- (p6);
     \draw [ shorten <=-0.08cm, shorten >=-0.15cm, -latex](p2) -- (p5);
     \draw (p8) -- (p10);
     \draw (p11) -- (p13);
     \draw [ shorten <=-0.08cm, shorten >=-0.15cm, -latex](p9) -- (p12);
  \end{scope}
\end{tikzpicture}
=\begin{cases}
  \begin{tikzpicture}[thick,baseline=(current bounding box.center)]
    \node (p1) at ( 0, -1) {};
    \node (p3) at ( 3,-1) {};
    \node (p4) at ( 0,0) {};
    \node (p6) at ( 3,0) {};
    \node (p7) at ( 0,1) {};
    \node (p9) at ( 3,1) {};
    \node (p2) at ( 1, -1.2) {$i$};
    \node (p5) at ( 2,0) {};
    \node (p10)at (2.05,-0.2){};
    \node (p8) at ( 1.5,1.2) {$l$};

    \node (p11)at (3.3, 0){=};

    \node (p12)at (3.6, -0.5){};
    \node (p13)at (4.6, -0.7){$i$};
    \node (p14)at (6.6, -0.5){};
    \node (p15)at (3.6, 0.5){};
    \node (p16)at (5.1, 0.7){$l$};
    \node (p17)at (6.6, 0.5){};
    %\node (p18)at (7.5, 0){si j=k};
    \begin{scope}
       \draw (p1) -- (p3);
       \draw (p4) -- (p6);
       \draw (p7) -- (p9);
       \draw [ shorten <=-0.08cm, shorten >=-0.15cm, -latex](p2) -- (p5);
       \draw [ shorten <=0.02cm, shorten >=-0.10cm, -latex](p10) -- (p8);

       \draw (p12) -- (p14);
       \draw (p15) -- (p17);
       \draw [shorten <=-0.08cm, shorten >=-0.1cm, -latex](p13) -- (p16);
    \end{scope}
  \end{tikzpicture} &\text{si }j=k\\
  0,&\text{en otro caso}\\
\end{cases}
\]
\end{document}

最后，你使用的tikz确实很冗长，可以简化很多。下面是我可能这样做的方法。事实证明，使用当前边界来设置基线不再那么有效，因为标签为 tikz 环境提供了一些“下方”的额外空间，因此我使用坐标 手动设置基线bl。

\tikzset{baseline=(bl.base), draw/.append style={thick}}
\[ \begin{tikzpicture}
      \coordinate(bl) at (1,0.4);  % set baseline
      \draw(0,0)--+(2,0);
      \draw(0,1)--+(2,0);
      \draw[-latex](0.6,0)node[below]{$i$}--(1.6,1)node[above]{$j$};
      \node at (2.3,0.5){$\cdot$};
      \draw(2.6,0)--+(2,0);
      \draw(2.6,1)--+(2,0);
      \draw[-latex](4.2,0)node[below]{$k$}--(3.6,1)node[above]{$l$};
    \end{tikzpicture}
  = \begin{cases}\space
    \begin{tikzpicture}
      \coordinate(bl) at (1,0.9);  % set baseline
      \draw(0,0)--+(2,0);
      \draw(0,1)--+(2,0);
      \draw(0,2)--+(2,0);
      \draw[-latex](0.6,0)node[below]{$i$}--(1.6,1);
      \draw[-latex](1.6,1)--(1,2)node[above]{$l$};
    \end{tikzpicture}
    =
    \begin{tikzpicture}
      \coordinate(bl) at (1,0.4);  % set baseline
      \draw(0,0)--+(2,0);
      \draw(0,1)--+(2,0);
      \draw[-latex](0.6,0)node[below]{$i$}--(1,1)node[above]{$l$};
    \end{tikzpicture},
   &\text{si }j=k\\
  0,&\text{en otro caso}\\
\end{cases}
\]

线条之间的空间比您原来的要大，因此您可能需要对此进行调整。我还使点k和j它们的线条之间的距离相同，以便案例环境中的第一个图表是正确的。这是此代码生成的结果：

在此处输入图片描述

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