Parallel capable? : yes

Parameter Name | Units | Type | Default | Description |

DX | double | 0.0 | non-functional misalignment (e.g., for girder) | |

DY | double | 0.0 | non-functional misalignment (e.g., for girder) | |

FITPOINT | long | `0` |
Supply local values of Twiss parameters, moments, floor coordinates, matrices, etc. for optimization? | |

GROUP | string | NULL | Optionally used to assign an element to a group, with a user-defined name. Group names will appear in the parameter output file in the column ElementGroup |

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 available, giving the reference value of at the marker location. - The quantities
`Cx`,`Cxp`,`Cy`,`Cyp`,`Cs`, and`Cdelta`will be available, giving coordinate centroid values from tracking to the marker location. - The quantities
`Sx`,`Sxp`,`Sy`,`Syp`,`Ss`, and`Sdelta`will be available, giving coordinate rms values at the marker location from tracking. - The quantity
`Particles`will be available, giving the number of particles tracked to the marker location. - The quantities
`s`will be available, giving at the marker location, where and .*ij* - The quantities
`betaxBeam`,`alphaxBeam`,`betayBeam`, and`alphayBeam`, which are the twiss parameters computed from the beam moments obtained by tracking, will be available. - The quantities
`R`will be available, for and , giving the accumulated first-order transport matrix to the marker location.*ij* - If the default matrix order (as set in
`run_setup`) is 2 or greater, the quantities`T`will be available, for , , and , giving the accumulated second-order transport matrix to the marker location.*ijk* - If Twiss parameter calculations are being performed (via
`twiss_output`with`output_at_each_step=1`), then the quantities`alphax`,`betax`,`nux`,`etax`,`etapx`, and`etaxp`, along with similarly-named quantities for the vertical plane, will be available, giving twiss parameter values at the marker location. Note that`etapx`and`etaxp`are the same, being alternate names for . If radiation integrals are requested, the values of the radiation integrals are available in the quantities`I1`,`I2`, etc. - If coupled Twiss parameter calculations are being performed (via
`coupled_twiss_output`with`output_at_each_step=1`), then the quantities`betax1`

,`betax2`

,`betay1`

,`betay2`

,`cetax`

,`cetay`

, and`tilt`

will be available. (These are the two beta functions for x and y, the coupled dispersion values for x and y, and the beam tilt). - If moments calculations are being performed (via
`moments_output`with`output_at_each_step=1`), then the quantities`s`, , giving the 21 unique elements of the sigma matrix. The quantities*ij*m`c`, , are also created, giving the 6 centroids from the moments computation. The*i*m`m`on the end of the symbols is to distinguish them from the moments computed from tracking. - If closed orbit calculations are being performed (via
`correct`or`closed_orbit`), then the quantities`xco`,`yco`,`xpco`, and`ypco`will be available, 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 available. These are, respectively, the three position coordinates, the three angle coordinates, and the total arc length at the marker location.

The misalignment controls for this element are non-functional, in the sense that they do not affect the beam.
However, when combined with external scripts and the `GROUP`

parameter, one can use this feature to
implement girder misalignments using pairs of markers to indicate the ends of the girders. A future version
of `elegant` will implement this internally.