MARK

If FITPOINT=0, this element results only in generation of additional output rows in the various files that contain output vs s. For example, Twiss parameters, closed orbits, and matrices vs s will all contain a row for each occurrence of each marker element.

If FITPOINT=1, the element has additional functionality in the context of optimizations. In particular, for occurrence N of the defined element Element, a series of symbols are created of the form Element#N.quantity, where quantity has the following values:

• The quantity pCentral will be created, giving the reference value of at the marker location.
• The quantities Cx, Cxp, Cy, Cyp, Cs, and Cdelta will be created, giving coordinate centroid values from tracking to the marker location.
• The quantity Particles will be created, giving the number of particles tracked to the marker location.
• The quantities sij will be created, giving at the marker location, where and .
• The quantities Rij will be created, for and , giving the accumulated first-order transport matrix to the marker location.
• If the default matrix order (as set in run_setup) is 2 or greater, the quantities Tijk will be created, for , , and , giving the accumulated second-order transport matrix to the marker location.
• If Twiss parameter calculations are being performed (via twiss_output), then the quantities alphax, betax, nux, etax, etapx, and etaxp, along with similarly-named quantities for the vertical plane, will be created, giving twiss parameter values at the marker location. Note that etapx and etaxp are the same, being alternate names for .
• If closed orbit calculations are being performed (via correct or closed_orbit), then the quantities xco, yco, xpco, and ypco will be created, giving the x and y closed orbits and their slopes, respectively, at the marker location.
• If floor coordinate calculations are begin performed (via floor_coordinates), then the quantities X, Y, Z, theta, phi, psi, and s will be created. These are, respectively, the three position coordinates, the three angle coordinates, and the total arc length at the marker location.