Remove bullet points and add intro/layout discussion

Author: davidlmobley

paper/basic_training.tex

@@ -1013,15 +1013,11 @@ \subsubsection{How to choose an appropriate timestep?}
 \subsection{Long range electrostatics}
 \todo[inline, color={yellow!20}]{DLM: I need to edit this section after we get Samarjeet's changes in; skipping for now.}
 \label{sec:lr_electrostatics}
-\begin{itemize}
-\item Cut-off is bad
-\item Need for special treatment
-\item Idea of an Ewald sum
-\item PPPM
-\item How to choose parameters
-\end{itemize}
 
 
+In view of the long-range nature of Coulombic interactions (Section~\ref{sec:classical_electrostatics}), handling of electrostatics is particularly important in many systems.
+Here we describe the motivation for the different treatments of these terms, and give an overview of the core idea of the basic algorithms typically employed.
+
 \subsubsection{Motivation}
 
 Calculation of non-bonded interaction is generally the most time-consuming step of classical energy calculation. While the number of type of bonded interactions remain unchanged during the course of MD simulation, the ones for non-bonded interactions have to be updated frequently as molecules move into and out of the cutoff regions specified for extramolecular interactions. Furthermore, $r^{-1} $ dependence  of coulombic interaction in a 3D space complicates the calculation in the following two ways :