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如何在 LaTeX 中使用 TikZ 绘制此图

tag-icon • tag-icon tikz-pgf
如何在 LaTeX 中使用 TikZ 绘制此图

如果有人能帮我画出所附的图表我将非常高兴。

在此处输入图片描述

这是我编写的代码：

\tikzstyle{block} = [draw, fill=cyan, regular polygon,
minimum height=3em, minimum width=6em]
\tikzstyle{input} = [coordinate]
\tikzstyle{output} = [coordinate]
\tikzstyle{pinstyle} = [pin edge={to-,thin,black}]

\begin{figure}[ht]
\centering
\begin{tikzpicture}[auto, node distance=2cm,>=latex']
\node [input, name=input] {};
\node [block, right of=sum] (Ablock) {A} edge [loop above] node {$\alpha$} (A);
\node [block, right of=Ablock, node distance=4cm] (Bblock) {B} edge [loop above] node {$\beta$} (A);
\draw [->] (Ablock) -- node[name=b] {a} (Bblock);
\begin{scope}[transform canvas={yshift=-2mm}]
\draw [->] (Bblock) -- node[name=a] {$b$} (Ablock);
\end{scope}
\node [output, right of=Bblock] (output) {};
\node [block, below of=b] (Cblock) {C} edge [loop below] node {$\gamma$} (C);
\draw [->] (sum) -- node {} (Ablock);
\draw [-] (Bblock) -| (output)  node [name=c] {};
\draw [-] (c) |- (Cblock);
\draw [-] (Cblock) -|  [near end] {} (sum);
\end{tikzpicture}
\end{figure}

在此处输入图片描述

答案1

库：

  • arrows.meta获取最新的箭头提示（以大写字母开头）。
  • positioning为了right = of …代替right of = …。
  • ext.paths.ortho用于路径操作r-rl和快捷方式|-和-|。
  • cd为shift left关键（较之有优点和缺点transform canvas）。

代码

\documentclass[tikz, border=5mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{
  arrows.meta,      % for newest arrow tips (capital letters)
  positioning,      % for better placement via left=of …
  shapes.geometric, % for regular polygon
  quotes,           % for "…" syntax
  ext.paths.ortho,  % for r-rl and |-/-| shortcuts
  cd}               % for shift left
\tikzset{
  cd/.code=\pgfqkeys{/tikz/commutative diagrams}{#1}%
}
\begin{document}
\begin{tikzpicture}[
  >=Latex,
  arr/.style={->, every edge quotes/.append style={
    execute at begin node=$, execute at end node=$},
    every loop/.append style={looseness=5}},
  dot/.style={circle, fill, draw, inner sep=+.7pt},
  block/.style={draw, fill=cyan, regular polygon, minimum size=6em},
]
\node[block] (C) {C};
\node[above=of C, dot] (c-above) {};
\node[above left =of c-above, block] (A) {A};
\node[above right=of c-above, block] (B) {B};

\coordinate[left=of A] (a-left);
\node[dot] (c-left) at (C-|a-left) {};

\path[arr, ortho/install shortcuts]
  (c-above) edge["c"'] (C)
  (A)       edge[|-]   (c-above)
  (B)       edge[|-]   (c-above)
  (C)       edge["d"]  (c-left)
  (c-left)  edge[|-]   (A)
  (A) edge[loop above, "\alpha"]            () % loops don't need a target
  (B) edge[loop above, "\beta"]             ()
  (C) edge[loop below, "\gamma" name=gamma] () % name this node
  (B) edge[to path={                           % so we can use it here
    r-rl ([yshift=-5mm]gamma.south)
    \tikztonodes % if you need nodes along the path
    -|(\tikztotarget)
  }] (c-left)
  (A) edge["a"] (B)
  [cd={shift left=2mm}]
  (B) edge["b"] (A)
;
\end{tikzpicture}
\end{document}

输出

在此处输入图片描述

答案2

我对你的代码进行了一些编辑，得到了这个结果！

\documentclass[tikz, border=20mm]{standalone}
\usetikzlibrary {shapes.geometric}
\tikzstyle{block} = [draw, fill=cyan, regular polygon,
minimum height=3em, minimum width=6em]
\tikzstyle{input} = [coordinate]
\tikzstyle{output} = [coordinate]
\tikzstyle{pinstyle} = [pin edge={to-,thin,black}]
\begin{document}
\begin{tikzpicture}[auto, node distance=2cm,>=stealth]
\node [input, name=input] {};
\node [block] (Ablock) {A} edge [loop above] node {$\alpha$} (A);
\node [block, right of=Ablock, node distance=4cm] (Bblock) {B} edge [loop above] node {$\beta$} (A);
\draw [->] (Ablock) -- node[name=b] {a} (Bblock);
\begin{scope}[transform canvas={yshift=-2mm}]
\draw [->] (Bblock) -- node[name=a] {$b$} (Ablock);
\end{scope}
\node [output, right of=Bblock] (output) {};
\node [block, right=2cm, below=4cm] (Cblock) {C} edge [loop below] node {$\gamma$} (C);
\draw[->] (Cblock)--++(-3.75,0)node[midway, below] {$d$} node[left=0.1cm] (ac) {};
\draw[->] (ac)|-(Ablock);
\draw[->] (Ablock.south)--++(0,-1)--++(1.75,0);
\draw[->] (Bblock.south)--++(0,-1)--++(-1.75,0) node[left=0.1cm] (c) {};
\fill[cyan] (c)circle(0.05);
\fill[cyan] (ac)circle(0.05);
\draw[->] (c)--(Cblock.north) node[left, midway] {$c$};
\draw[->] (Bblock)--++(2,0)--++(0,-8)--++(-8,0)--(ac);
\end{tikzpicture}
\end{document}

在此处输入图片描述

看来，当在另一个文档类中执行此代码时，它不会产生预期的结果。要解决此问题，您有两个选择。首先，您可以适当调整坐标，因为一切都是成比例的。或者，您可以重新编译此处描述的所有内容，并使用包将其包含在您的文件中graphicx（例如\includegraphics[scale=0.75]{diagram.pdf}：）。这也应该有效。

但是，我强烈建议您花时间了解@Qrrbrbirlbel 的答案，因为它条理清晰，涉及从头开始重新定义所有内容。在我的回答中，我只编辑了您的代码以获得所需的图表。

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