\documentclass{standalone}
\input{common-headers}
\input{sigles}
\begin{document}
\begin{tikzpicture}
  \pgfplotsset{width=.6\textwidth}
  \begin{axis}[%
       xlabel=Itérations
      ,scale only axis
      ,ylabel=Quantité normalisée
      ,ymin=0,ymax=1.1
      ,xmin=0,xmax=1000
      ,no markers
      ,legend style={draw=none,at={(0.98,0.5)},anchor=east}
      ,legend cell align=left]
    \addplot+[blue!50] table[x=ITER,y=NONITERNORM] {data/speedup2.data};
    \addplot+[black] table[x=ITER,y=OPTITERNORM] {data/speedup2.data};
    \addplot+[black,dashed] table[x=ITER,y=ACTIVENORM] {data/speedup2.data};
    \legend{Simulation normale, Simulation optimisée, Cellules actives}
  \end{axis}
\end{tikzpicture}
\end{document}