Running <tt>allocchain</tt> in parallel mode. Each replica occupies one CPU. 
Effective only when MD++ is compiled for parallel runs, e.g. with <tt>SYS = mpicc</tt>
or <tt>SYS = mpigpp</tt>. 

<p>
Also see <tt>nebrelax_parallel</tt>, <tt>stringrelax_parallel</tt>.

