latextikzgraph-drawing

Tikz: draw edge from node to label of another edge


I'm trying to figure out how to draw an edge between a node in tikz and the label of an edge between two other nodes. Here's an example of what I'm trying to do:

enter image description here

Here's my code:

\documentclass[11pt]{article}
\usepackage[margin=1in, top=1.5in]{geometry}
\usepackage{amsmath,amssymb,bbm}
\usepackage{graphicx}
\usepackage{tikz}
\usetikzlibrary{arrows, positioning}

\setlength{\parindent}{0.25in}
\newcommand{\assign}{:=}
\usepackage[hang,small,bf]{caption}


\begin{document}

\begin{figure}[!h]
  \centering
  \begin{tikzpicture}[shorten >=1pt,node distance=3cm,on grid,auto]
    \tikzstyle{state}=[shape=circle,thick,draw,minimum size=1.5cm]

    \node[state] (A1) {$A_1$};
    \node[state,above of=A1] (B1) {$B_1$};
    \node[state,above of=B1] (C1) {$C_1$};

    \node[state,right of=A1] (A2) {$A_2$};
    \node[state,above of=A2] (B2) {$B_2$};
    \node[state,above of=B2] (C2) {$C_2$};



    \path[->,draw,thick]
    (A1) edge node {$l_A$} (B2)
    (B1) edge node {$l_B$} (B2)

    ;

  \end{tikzpicture}
  \caption{Model}
  \label{fig:f1}
\end{figure}


\end{document}

Can someone tell me how I can get this effect?

Thanks!


Solution

  • According to the documentation,

    You may also add the option name=<name> to the option list; it has the same effect [as providing a node name with (name)]

    With your example, this gives:

    \documentclass[11pt]{article}
    \usepackage[margin=1in, top=1.5in]{geometry}
    \usepackage{amsmath,amssymb,bbm}
    \usepackage{graphicx}
    \usepackage{tikz}
    \usetikzlibrary{arrows, positioning}
    
    \setlength{\parindent}{0.25in}
    \newcommand{\assign}{:=}
    \usepackage[hang,small,bf]{caption}
    
    
    \begin{document}
    
    \begin{figure}[!h]
      \centering
      \begin{tikzpicture}[shorten >=1pt,node distance=3cm,on grid,auto]
        \tikzstyle{state}=[shape=circle,thick,draw,minimum size=1.5cm]
    
        \node[state] (A1) {$A_1$};
        \node[state,above of=A1] (B1) {$B_1$};
        \node[state,above of=B1] (C1) {$C_1$};
    
        \node[state,right of=A1] (A2) {$A_2$};
        \node[state,above of=A2] (B2) {$B_2$};
        \node[state,above of=B2] (C2) {$C_2$};
    
    
    
        \path[->,draw,thick]
        (A1) edge node[name=la] {$l_A$} (B2)
        (B1) edge node[name=lb] {$l_B$} (B2)
    
        ;
        \draw[->, thick, bend left=15]  (C1) edge (la) edge (lb); 
    
      \end{tikzpicture}
      \caption{Model}
      \label{fig:f1}
    \end{figure}
    
    
    \end{document}
    

    screenshot of output