树上节点之间的 Latex 连接线

Question

如何连接树上的 2 个水平节点？也就是说，我想将 z1 连接到 z2。但该线应继续延伸到 z2 的右侧和 z1 的左侧以显示连续性。对于 theta 1 和 theta 2 也是如此。

我当前的乳胶命令：

\begin{tikzpicture}[level distance=1.2cm, 
                    level 1/.style={sibling distance=4cm},
                    level 2/.style={sibling distance=1cm}
                   ]
\centering
\tikzstyle{every node}=[circle,draw]

\node (Root) [black] {$z_{1}$}
    child {
    node {$\theta_{1}$} 
    child { node {$\varphi_{1}$} edge from parent node[left,draw=none]{} }
    child { node {$\varphi_{2}$} }
    child { node {$\varphi_{3}$} }
};
\hspace*{4cm}\node (Root) [black] {$z_{2}$}
child {
    node {$\theta_{2}$}
    child { node {$\varphi_{1}$} }
    child { node {$\varphi_{2}$} }
    child { node {$\varphi_{3}$} }
    child { node {$\varphi_{4}$} }
};

\end{tikzpicture}

Answer 1

我对你的代码做了一些改进：

1. 使用positioning库的right=4cm of Root1语法。
2. 使用\tikzset而不是\tikzstyle。
3. 将节点重命名(Root)为(Root1)并(Root2)使用 连接它们\draw。

---

\documentclass[tikz]{standalone}
\usetikzlibrary{positioning}
\tikzset{every node/.style = {circle,draw}}
\begin{document}
\begin{tikzpicture}[level distance=1.2cm, 
        level 1/.style={sibling distance=4cm},
        level 2/.style={sibling distance=1cm}
    ]
    \node (Root1) [black] {$z_{1}$}
    child {
        node {$\theta_{1}$} 
        child { node {$\varphi_{1}$} edge from parent node[left,draw=none]{} }
        child { node {$\varphi_{2}$} }
        child { node {$\varphi_{3}$} }
    };
    \node[right=4cm of Root1] (Root2) [black] {$z_{2}$}
    child {
        node {$\theta_{2}$}
        child { node {$\varphi_{1}$} }
        child { node {$\varphi_{2}$} }
        child { node {$\varphi_{3}$} }
        child { node {$\varphi_{4}$} }
    };
    \draw (Root1) -- (Root2);
\end{tikzpicture}
\end{document}