Computes central symmetry deviation (CSD) parameter for each
atom and store them in the <tt>TOPOL</tt> array.

<p>
Requires <tt>NCS</tt>  to be set
(number of nearest neighbors in CSD calculation).

For FCC crystal, use <tt>NCS = 12</tt>.  For BCC crystal, use <tt>NCS = 8</tt>.

<p>
Also see <tt>GnuPlotHistogram</tt>.
