I'd like to create a tree with edges made from two separate arrows as shown in picture:
But I don't know how to change the edge to 'two separate arrows for each edge' Currently, I could only do the diagram below:
Below is the sample code:
\documentclass{article}
\usepackage[latin1]{inputenc}
\usepackage{tikz}
\usetikzlibrary{trees}
\begin{document}
\pagestyle{empty}
\tikzstyle{level 1}=[level distance=3.5cm, sibling distance=3.5cm]
\tikzstyle{level 2}=[level distance=3.5cm, sibling distance=2cm]
\tikzstyle{bag} = [text width=4em, text centered]
\begin{tikzpicture}[sloped]
\node[bag] {1}
child {
node[bag] (2) {2}
child {
node (4) {4}
edge from parent [<->, thick]
node[above] {e}
node[below] {f}
}
child {
node (5) {5}
edge from parent [<->, thick]
node[above] {g}
node[below] {h}
}
edge from parent [<->, thick]
node[above] {a}
node[below] {b}
}
child {
node[bag] (3) {3}
child {
node (6) {6}
edge from parent [<->, thick]
node[above] {i}
node[below] {j}
}
child {
node (7) {7}
edge from parent [<->, thick]
node[above] {k}
node[below] {l}
}
edge from parent [<->, thick]
node[above] {c}
node[below] {d}
};
\path (2) -- (3) node [midway] {$\cdots$};
\path (4) -- (5) node [midway] {$\cdots$};
\path (6) -- (7) node [midway] {$\cdots$};
\end{tikzpicture}
\end{document}
Appreciate any help. Thanks!