small improvement of figure legend

Author: simongravelle

lammps-tutorials.tex

@@ -822,12 +822,12 @@ \subsubsection{My first input}
 \begin{figure}
 \centering
 \includegraphics[width=\linewidth]{LJ-energy}
-\caption{Potential energy ($p_\text{e}$) of the binary mixture simulated
-  during \hyperref[lennard-jones-label]{Tutorial 1} as a function of the
-  step during energy minimization (a) and as a function of time during
-  molecular dynamics in the NVT ensemble (b), and kinetic energy
-  ($k_\text{e}$) during energy minimization (c) and during molecular
-  dynamics (d).}
+\caption{(a) Potential energy ($p_\text{e}$) of the binary mixture
+as a function of the step during energy minimization in \hyperref[lennard-jones-label]{Tutorial 1}.
+(b) Potential energy ($p_\text{e}$) as a function of time during
+molecular dynamics in the NVT ensemble.  (c) Kinetic energy
+($k_\text{e}$) during energy minimization.  (d) Kinetic energy
+($k_\text{e}$) during molecular dynamics.}
 \label{fig:evolution-energy}
 \end{figure}