analytic_function.tex

\documentclass{article}
\usepackage{geometry}
 \geometry{
 letterpaper,
 left=1in,
 right=1in,
 top=1in,
 bottom=1in,
 }
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{amsmath,float}
\floatplacement{figure}{H}
\usepackage{hyperref}
\usepackage{tikz,pgfplots}
\pgfplotsset{compat=1.12}

\graphicspath{{./images/}}
\input{math_commands}

% used tikz libraries
\usetikzlibrary{patterns}
\usetikzlibrary{arrows}
\usetikzlibrary{calc}
\usetikzlibrary{intersections}
\usetikzlibrary{trees}
\usetikzlibrary{positioning}
\usetikzlibrary{arrows}
\usetikzlibrary{chains}
\usetikzlibrary{decorations.shapes}
\usetikzlibrary{decorations.pathreplacing}
\usetikzlibrary{decorations.pathmorphing}
\usetikzlibrary{decorations.markings}
\usetikzlibrary{shapes}
\usetikzlibrary{matrix}

\begin{document}

\begin{figure}[!ht]
\centering
\begin{tikzpicture}

% plot curve for first axis
\begin{axis}[
width=11cm,
height=8cm,
xmin=0, xmax=1,
ylabel={$u_1$ [m/s]},
xlabel={$t^*$},
axis y line=left,
legend style={draw=none}
]
\addplot[mark=o] table[x index=0,y index=1] {data/moy_phase_4hz.dat};

% add label to access plot from first axis
\label{plot_one};
\end{axis}

% plot curves for second axis
\begin{axis}[
width=11cm,
height=8cm,
xmin=0, xmax=1,
ylabel={$u_2$ [m/s]},
xlabel={$t^*$},
axis y line=right,
ylabel style={yshift=-0.5em},
axis x line=none
]

% add the item of the first axis referencing axis !!
\addlegendimage{/pgfplots/refstyle=plot_one}\addlegendentry{$u_1$: Piston, 4~Hz}

% then we use add plot for curves on second axis
\addplot[color=red,mark=x] table[x index=0,y index=1] {data/moy_phase_34hz.dat};
\addplot[domain=0:1,dashed,thick]{0.030759*sin(deg(2*pi*x)-7)+0.730899065};

% that we also create legend entry
\addlegendentry{$u_2$: P.-à-f., 34~Hz}
\addlegendentry{Fonction sinus}
\end{axis}
\end{tikzpicture}
\caption{Two axis from different file using one combined legend}
\end{figure}

\end{document}