PGF/Tikz

Write a figure

The preamble of the latex file must contain:

\usepackage{tikz}

Some optional libraries could be add like this:

\usetikzlibrary{calc}

To start a figure, the code must be inside the tikzpicture environment like this:

\begin{tikzpicture} ... TikZ code here...  \end{tikzpicture}

exemple

% Author: Quintin Jean-Noël
% <http://moais.imag.fr/membres/jean-noel.quintin/>
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary[topaths]
% A counter, since TikZ is not clever enough (yet) to handle
% arbitrary angle systems.
\newcount\mycount
\begin{document}
\begin{tikzpicture}[transform shape]
%the multiplication with floats is not possible. Thus I split the loop
%in two.
\foreach \number in {1,...,8}{
  % Computer angle:
    \mycount=\number
    \advance\mycount by -1
    \multiply\mycount by 45
    \advance\mycount by 0 
    \node[draw,circle,inner sep=0.125cm] (N-\number) at (\the\mycount:5.4cm) {};
} 
\foreach \number in {9,...,16}{
  % Computer angle:
    \mycount=\number
    \advance\mycount by -1
    \multiply\mycount by 45
    \advance\mycount by 22.5
    \node[draw,circle,inner sep=0.125cm] (N-\number) at (\the\mycount:5.4cm) {};
} 
\foreach \number in {1,...,15}{
  \mycount=\number
    \advance\mycount by 1 
    \foreach \numbera in {\the\mycount,...,16}{
      \path (N-\number) edge[->,bend right=3] (N-\numbera)  edge[<-,bend
        left=3] (N-\numbera);
    }     
}
\end{tikzpicture}
\end{document}