两个图中节点之间的虚线

Question

我需要为我的硕士论文报告创建一些匹配图，如下所示：

我找到了一种叫做 PG 3.0 的东西，它可以制作图表，但我不知道如何制作虚线或树的名称（参见上图中的 T1 和 T2）

\documentclass[tikz,border=10pt]{standalone}
\usetikzlibrary{graphdrawing}
\usetikzlibrary{graphs}
\usegdlibrary{trees}
\begin{document}
\begin{tikzpicture}[>=stealth, every node/.style={circle, draw, minimum size=0.75cm}]
\graph [tree layout, grow=down, fresh nodes, level distance=0.5in, sibling distance=0.5in]
    {
        R -> { 
          a,
          b,
          c
        },
        R -> {
            a, 
            q,
            c
        }
    };
\end{tikzpicture}
\end{document}

Answer 1

下面我提出两个选择：

1. 这是一个使用“pure”TikZ和两个\graphs 的选项；命名它们允许使用节点来绘制线条：

   \documentclass[tikz,border=10pt]{standalone}
   \usetikzlibrary{graphdrawing}
   \usetikzlibrary{graphs}
   \usegdlibrary{trees}
   
   \begin{document}
   
   \begin{tikzpicture}[>=stealth, every node/.style={circle, draw, minimum size=0.75cm}]
   % tree to the left
   \graph[tree layout, grow=down, fresh nodes, level distance=0.5in, sibling distance=0.5in]
       {[name=left]
           R -> { 
             a -> {
                 b, 
                 c
                 },
             d  
           },
       };
   % tree to the right
   \begin{scope}[xshift=4cm]    
   \graph [tree layout, grow=down, fresh nodes, level distance=0.5in, sibling distance=0.5in]
       {[name=right]
           R -> { 
             a' -> {
                 b, 
                 {[name=m] b}
                 },
             d -> {
                 e, 
                 f
                 }  
           },
       };
   \end{scope}
   
   % naming the trees
   \node[draw=none,label={above left:$T_{1}$}] at (left R) {};    
   \node[draw=none,label={above left:$T_{2}$}] at (right R) {};    
   
   % connecting the trees
   \draw[dashed]
         (left R) to[out=30,in=150] (right R);
   \draw[dashed]
         (left a) to[out=40,in=140] (right a');
   \draw[dashed]
         (left d) to[out=40,in=140] (right d);
   \draw[dashed]
         (left b) to[out=-40,in=-140] (right b);
   \draw[dashed]
         (left b) to[out=-40,in=-140] (right m b);
   \end{tikzpicture}
   
   \end{document}
   

   

2. 这是现在使用这个时间的另一种选择forest包和一棵树（同样，关键是要有一个可用的命名机制）：

   \documentclass[varwidth,border=10pt]{standalone}
   \usepackage{forest}
   
   \begin{document}
   \begin{forest}
   for tree={
     draw,
     circle,
     minimum size=20pt
   }
   [,phantom,s sep=1cm
   [R,name=rl,
     [a,name=al
       [b,name=bl]
       [b]
     ]
     [d,name=dl
     ]
   ]
   [R,name=rr
     [a',name=ar
       [b,name=bri]
       [b,name=brii]
     ]
     [d,name=dr
       [e]
       [f]
     ]
   ]
   ]
   % naming the trees
   \node[inner sep=7pt,label={above left:$T_{1}$}] at (rl) {};
   \node[inner sep=7pt,label={above left:$T_{2}$}] at (rr) {};
   % connecting the trees
   \draw[dashed]
         (rl) to[out=30,in=150] (rr);
   \draw[dashed]
         (al) to[out=40,in=140] (ar);
   \draw[dashed]
         (dl) to[out=40,in=140] (dr);
   \draw[dashed]
         (bl) to[out=-40,in=-140] (bri);
   \draw[dashed]
         (bl) to[out=-40,in=-140] (brii);
   \end{forest}
   
   \end{document}
   

   

Answer 2

下面是另一个建议，使用\graph内部有两个子图：

\documentclass[tikz,border=10pt]{standalone}
\usetikzlibrary{graphs,graphdrawing}
\usegdlibrary{trees}
\begin{document}
\begin{tikzpicture}[
    >=stealth,
    subgraph text top=text centered,
  ]
\graph[
    tree layout,
    nodes={circle, draw, minimum size=0.75cm},
    level distance=0.5in,
    sibling distance=0.5in,
    component sep=3em % sep between the two subgraphs/trees
  ]
  {
    $T_{1}$//%first subgraph
      {[name=left]R->{a->{b,c},d}};
    $T_{2}$[xshift=-1em]//% second subgraph
      {[name=right]R->{a/a'->{bl/b,br/b},d->{e,f}}};
  };
  \foreach \n in {R,a,d}
    \draw[dashed](left \n)to[out=30,in=150](right \n);
  \foreach \n in {l,r}
    \draw[dashed](left b)to[out=330,in=210](right b\n);
\end{tikzpicture}
\end{document}