&closed_orbit STRING output = NULL; long output_monitors_only = 0; long start_from_centroid = 1; long start_from_dp_centroid = 1; double closed_orbit_accuracy = 1e-12; long closed_orbit_iterations = 10; double iteration_fraction = 1; long fixed_length = 0; long start_from_recirc = 0; long verbosity = 0; &end
output-- The (incomplete) name of an SDDS file to which the closed orbits will be written. Recommended value: ``%s.clo''.
output_monitors_only-- If non-zero, indicates that the closed orbit output should include only the data at the locations of the beam-position monitors.
start_from_centroid-- A flag indicating whether to force the computation to start from the centroids of the beam distribution.
start_from_dp_centroid-- A flag indicating whether to force the computation to use the momentum centroid of the beam for the closed orbit. This can allow computing the closed orbit for an off-momentum beam, then starting the beam on that orbit using the
center_on_orbitparameters of the
trackcommand. In contrast to the
start_from_centroid, this command doesn't force the algorithm to start from the beam transverse centroids.
closed_orbit_accuracy-- The desired accuracy of the closed orbit, in terms of the difference between the start and end coordinates, in meters.
closed_orbit_iterations-- The number of iterations to take in finding the closed orbit.
iteration_fraction-- Fraction of computed change that is used each iteration. For lattices that are very nonlinear or close to unstable, a number less than 1 can be helpful. Otherwise, it only slows the simulation.
fixed_length-- A flag indicating whether to find a closed orbit with the same length as the design orbit by changing the momentum offset.
start_from_recirc-- A flag indicating whether to compute the closed orbit from the recirculation (
recirc) element in the beamline. In general, if one has a recirculation element, one should give this flag.
verbosity-- A larger value results in more printouts during the computations.