Usage: <tt>input = [ <i>smin smax nmax</i> ] WalkonChain</tt>

<p>
Sample transition paths connecting two states (most spins down v.s. most spins up)
by randomly picking a point on the existing path and generate a trajectory
(by <tt>SampleMCpath</tt>) with this 
point as the initial condition.  The trajectory is then used to replace half of the
original path to generate a new path.

<p>
The parameters <tt><i>smin smax nmax</i></tt> are passed to <tt>SampleMCpath</tt>.

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

