# Simple way to move side by side tikzpicture?

I have two graph side by side in two different tikzpicture. But I'd like to move the left one up a bit. I know an elaborate way to do it but I am sure the is a simple way. The options yshift=-2cm doesnt seem to do it. Here is the code sample:

\begin{center}
\begin{tikzpicture}[sommet/.style={circle, draw},yshift=-2cm]
\centering
% Sommets
\node[sommet] (s1) at (1.5,3) {$s_1$};
\node[sommet] (s2) at (3,0) {$s_2$};
\node[sommet] (s3) at (0,0) {$s_3$};
% Arêtes
\path (s1) edge node[xshift=-0.23cm] {$a_1$}(s2);
\path (s2) edge node[yshift=0.23cm] {$a_2$} (s3);
\path (s3) edge node[xshift=+0.29cm] {$a_3$}(s1);
\end{tikzpicture}
\begin{tikzpicture}[sommet/.style={circle, draw}]
% Sommets
\node[sommet] (s1) at (1.5,3) {$s_1$};
\node[sommet] (s2) at (3,0) {$s_2$};
\node[sommet] (s3) at (0,0) {$s_3$};
\node[sommet] (a1) at (3,2) {$a^{\prime}_1$};
\node[sommet] (a2) at (1.5,-1) {$a^{\prime}_2$};
\node[sommet] (a3) at (0,2) {$a^{\prime}_3$};
% Arêtes
\path (a1) edge (s1) edge (s2);
\path (a2) edge (s2) edge (s3);
\path (a3) edge (s3) edge (s1);
\path (s1) edge node[xshift=-0.23cm] {$a_1$}(s2);
\path (s2) edge node[yshift=0.23cm] {$a_2$} (s3);
\path (s3) edge node[xshift=+0.29cm] {$a_3$}(s1);
\end{tikzpicture}
\end{center}


yshift does nothing because it only adds a value to the coordinates in TikZ's coordinate system, which has nothing to do with how the tikzpicture is drawn on the page.

If you want them vertically centered, add baseline=(current bounding box.center) to both tikzpictures. If you want the two triangles vertically aligned, add baseline=(s3.south) as an option to the second tikzpicture.

(I also changed node[xshift=0.23cm] to node[right] and similar, which seems like an easier way of positioning the edge labels.)

\documentclass[]{article}
\usepackage{tikz}
\begin{document}
\begin{center}
\begin{tikzpicture}[sommet/.style={circle, draw},baseline=(current bounding box.center)]
\centering
% Sommets
\node[sommet] (s1) at (1.5,3) {$s_1$};
\node[sommet] (s2) at (3,0) {$s_2$};
\node[sommet] (s3) at (0,0) {$s_3$};
% Arêtes
\path (s1) edge node[left] {$a_1$}(s2);
\path (s2) edge node[above] {$a_2$} (s3);
\path (s3) edge node[right] {$a_3$}(s1);
\end{tikzpicture}
\begin{tikzpicture}[sommet/.style={circle, draw},baseline=(current bounding box.center)]
% Sommets
\node[sommet] (s1) at (1.5,3) {$s_1$};
\node[sommet] (s2) at (3,0) {$s_2$};
\node[sommet] (s3) at (0,0) {$s_3$};
\node[sommet] (a1) at (3,2) {$a^{\prime}_1$};
\node[sommet] (a2) at (1.5,-1) {$a^{\prime}_2$};
\node[sommet] (a3) at (0,2) {$a^{\prime}_3$};
% Arêtes
\path (a1) edge (s1) edge (s2);
\path (a2) edge (s2) edge (s3);
\path (a3) edge (s3) edge (s1);
\path (s1) edge node[left] {$a_1$}(s2);
\path (s2) edge node[above] {$a_2$} (s3);
\path (s3) edge node[right] {$a_3$}(s1);
\end{tikzpicture}

\begin{tikzpicture}[sommet/.style={circle, draw}]
\centering
% Sommets
\node[sommet] (s1) at (1.5,3) {$s_1$};
\node[sommet] (s2) at (3,0) {$s_2$};
\node[sommet] (s3) at (0,0) {$s_3$};
% Arêtes
\path (s1) edge node[left] {$a_1$}(s2);
\path (s2) edge node[above] {$a_2$} (s3);
\path (s3) edge node[right] {$a_3$}(s1);
\end{tikzpicture}
\begin{tikzpicture}[sommet/.style={circle, draw},baseline=(s3.south)]
% Sommets
\node[sommet] (s1) at (1.5,3) {$s_1$};
\node[sommet] (s2) at (3,0) {$s_2$};
\node[sommet] (s3) at (0,0) {$s_3$};
\node[sommet] (a1) at (3,2) {$a^{\prime}_1$};
\node[sommet] (a2) at (1.5,-1) {$a^{\prime}_2$};
\node[sommet] (a3) at (0,2) {$a^{\prime}_3$};
% Arêtes
\path (a1) edge (s1) edge (s2);
\path (a2) edge (s2) edge (s3);
\path (a3) edge (s3) edge (s1);
\path (s1) edge node[left] {$a_1$}(s2);
\path (s2) edge node[above] {$a_2$} (s3);
\path (s3) edge node[right] {$a_3$}(s1);
\end{tikzpicture}
\end{center}
\end{document}