Let's say I have a triangle like this which is easily generated by pgf.
\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[
vertex/.style={circle, draw=blue!60, fill=blue!40, minimum size=2mm},
line/.style = {draw, thick}
]
\newcommand\mylength{30mm}
\coordinate (A) at ( 90: \mylength);
\coordinate (B) at (210: \mylength);
\coordinate (C) at (-30: \mylength);
\path [line] (A) -- (B);
\path [line] (B) -- (C);
\path [line] (C) -- (A);
\node [vertex] at (A) {1};
\node [vertex] at (B) {2};
\node [vertex] at (C) {3};
\end{tikzpicture}
\end{document}
And this is the diagram I want to draw:
1
/ \
/ \
2-----3
/ \
/ \
1 1
\ \
\ \
2-----3 3
As some of you may notice it, the drawing is about a deletion-contraction recurrence. A triangle at the top node is decomposed into two subgraphs:
- The left child is obtained by deleting an edge 1-2
- The right child is obtained by contracting an edge 1-2 such that this edge shrinks to a single point by merging two endpoints 1 and 2 into a 'new 1' node, followed by deleting multiple edges.
I want to keep this process going until the tree reaches into much smaller graphs, so the final output will be much bigger. Even for the small tree of depth 1, I don't know what's the best way to draw such a tree. Any hints or suggestions?
Added: I used a triangle in this example because it's the simplest drawing that can be used as an example. The graph of interest can be any arbitrary graph and what I prefer is to wrap each graph in some kind of 'node' or 'box' and then connect each container node are connected as a node in a tree. What's the best way to do this?
Sorry for any confusion.