Typesetting digraph with weighted edges, varying vertex size, multiple lines in vertex

Question

I would like to draw the graph displayed in the following picture with TikZ and also do some modifications:

Firstly I want to carry the labels of the nodes to the inside as a second line. For instance inside node a it will display a, and then below (0.5 70/70) (preferably with a smaller font than a).

Moreover I would like to change the sizes of the nodes wrt. the the numeric value displayed in the label. So as an example the node e will be approximately twice as big as node a.

Answer 1

Here's one possibility:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning}

\definecolor{myyellow}{RGB}{255,255,150}

\newcommand\mytext[3][\scriptsize]{#2\\#1 #3}
\newcommand\mynode[4][]{%
  \node[mynode,#1,text width=\the\dimexpr#2cm*3] (#3) {\mytext{#3}{#2 #4}}; 
}

\begin{document}

\begin{tikzpicture}[
node distance=2cm,
mynode/.style={
  circle,
  draw,
  fill=myyellow,
  align=center}
]
\mynode{0.67}{d}{(130/61)}
\mynode[below=of d]{0.45}{c}{(130/61)}
\mynode[below=of c]{0.50}{a}{(130/61)} 
\mynode[left=of a]{0.67}{b}{(130/61)} 
\mynode[right=of c]{0.95}{e}{(130/61)}
\draw[->] 
  (d) -- node[rotate=90,below] {\mytext[\normalsize]{0.9}{(72/8)}} (c); 
\draw[->] 
  (c) -- node[rotate=90,below] {\mytext[\normalsize]{0.9}{(72/8)}} (a);
\draw[->] 
  (d) -- node[sloped,below] {\mytext[\normalsize]{0.9}{(72/8)}} (b); 
\draw[->] 
  (e) -- node[sloped,below] {\mytext[\normalsize]{0.9}{(72/8)}} (a); 
\draw[->] 
  (b) to[bend left] node[above] {\mytext[\normalsize]{0.9}{(72/8)}} (a); 
\draw[->] 
  (a) to[bend left] node[below] {\mytext[\normalsize]{0.9}{(72/8)}} (b); 
\end{tikzpicture}

\end{document}

The syntax for the \mynode command is

\mynode[<options>]{<value>}{<name>}{<additional text>}

The optional argument passes <options> to a \node; <value> will be used to internally calculate the node size, and also in the label; <name> will be used for the label and to name the node, <additional text> is the text that will accompany <value> in the label.

Answer 2

Here is one way you can have text in the nodes and also have the node scaled to the weight:

Notes:

• You need to carefully select the value of the \DefaultSize based on the range of your data.
• As per Qrrbrbirlbel's suggestion I have scaled based on the sqrt of the size parameter so as to keep the area proportional to the weight.

Code:

\documentclass{article}
\usepackage{tikz}

\newcommand*{\DefaultRadius}{1.2cm}%

\tikzset{My Style/.style={circle,draw=black, ultra thick, fill=yellow!40,align=center}}

\newlength{\NodeSize}
\newcommand{\MyNode}[4][]{%
    % #1 = optional node paramaters
    % #2 = label
    % #3 = scale
    % #4 = additional text
    \pgfmathsetlength{\NodeSize}{2*\DefaultRadius*sqrt(#3)}%
    \node [My Style, minimum size=\NodeSize,#1] (#2) {#2 \\ {\tiny #3 #4}}
}%
\begin{document}
\begin{tikzpicture}
\MyNode{d}{1.0}{70/70};
\MyNode[xshift=4.0cm,fill=cyan!25,draw=red]{c}{1.5}{70/70};
\MyNode[xshift=8.0cm,fill=green!20]{c}{0.5}{70/70};
\end{tikzpicture}
\end{document}