modified the caption for decay plot

Author: samarjeet

paper/basic_training.tex

@@ -1078,7 +1078,8 @@ \subsubsection{ Ewald Summation}
 \begin{figure}[h]
 \centering
 \includegraphics[width=\linewidth]{py_decay_comparison.pdf}
-    \caption{Comparison of decay of the original $r^{-1}$ term for Coulomb interactions (blue,*), the resulting direct-space term after Gaussian screening (black,-) and the $r^{-6}$ in van der Waals term (red, -.).  }
+    \caption{Comparison of decay of the original $r^{-1}$ term for Coulomb interactions (blue,*), the resulting direct-space term after Gaussian screening (black,-) and the $r^{-6}$ in van der Waals term (red, -.). 
+    Note: erfc(r)/r has been scaled to show relative decay of each term. }
 \label{decay}
 \end{figure}