If <tt>printfreq > 0</tt>, then the current time step information <tt>curstep</tt>
is printed to the terminal (if <tt>setnolog</tt> has been set) or the A.log file (if
<tt>setnolog</tt> has not bee set) during the MD simulation every <tt>printfreq</tt>
steps.  In Monte Carlo simulations other diagnostic information, such as acceptance 
ratio, is also printed.
