small fix

Author: simongravelle

lammps-tutorials.tex

@@ -2485,7 +2485,7 @@ \subsubsection{System preparation}
 
 When running the \flecmd{minimize.lmp} file with LAMMPS, you should observe that the
 the temperature reaches the desired value of $300\,\text{K}$, and that the total
-energy reaches a plateau.  The generated file
+energy reaches a plateau (Fig.\,\ref{fig:NANOSHEAR-minimization}).  The generated file
 \flecmd{minimize.data} contains the final state of the system.
 
 \begin{figure}