Usage: <tt>input = <i>pn</i> initpath</tt>

<p>
Initialize the path to be a random path going from all spin down (-1) to all spin up (+1).
The path will be used in future path sampling simulations.
There are three paths in the MD++/ising model: <tt>pathA</tt>, <tt>pathB</tt>, <tt>pathC</tt>.
Which one gets initialized by <tt>initpath</tt> depends on the value of <tt><i>pn</i></tt>
(1 for <tt>pathA</tt>, 2 for <tt>pathB</tt>, 3 for <tt>pathC</tt>).

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