  Symplectic tracking of beam particles using point magnets is achieved using a
reference orbit made of circular arcs and straight lines that join smoothly
with each other. For this choice of the reference orbit, results are given for
the transfer functions, transfer matrices, and the transit times of the magnets
and drift spaces. These results provide a symplectic integrator, and allow the
linear orbit parameters to be computed by multiplying transfer matrices. It is
shown that this integrator is a second-order integrator, and that the transfer
functions can be derived from a hamiltonian.
