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For LCLS, we will pre-compute the optics from the lattice, to produce the XAL files which include the Twiss params, so each modeling application doesn't have to track a lattice for itself before starting. The online modeling "tracker" will be that in XAL (primarily in the gov.sns.xal.model package). The output of this phase will be the Twiss parameters of each element of the beamline. A second probe can calculate the transfer matrices (R-matrices). The Twiss param outputs will be captured in a series of second XAL files. There is presently no file-handling code in XAL for statically recording the R-matrices or global parameters (path length, energy, betamax), so new output files will be designed for that (either extending the XAL syntax, or creating some other XML file). proposal: adapt probe for coupled write tracker to probe Twiss params and (coupled - see Red Flags) R-matrices, and additionally output global parameters to a file.
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Windows filesystem.
If we do require native execution on Windows that decision should be made clearly and early, and resources assigned to implement the common executable and configuration file distribution so that Unix and Windows running applications are in sync and see the same configuration files. Java Web Start and Eclipse update site technology may be places to find solutions.
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XAL Plane Coupled modeling.
The existing XAL probes for calculating R-matrices, run on either the X-plane or Y-plane and returns only a 2x2 matrix for each element. That is, it's uncoupled. This is reflected in the fact that only the Twiss parameters can be stored into an XAL file - it only contains uncoupled optics. It may be that XAL is in fact tracking a plane coupled system, but only returning the X or Y plane block-matrices - need to verify. So, if plane coupled orbit correction is important for us, we need to verify what XAL is doing, add at least 4x4 and probe API, also probably also 6x6 tracking.
XAL Modelled acceleration and solenoid. XAL does not model acceleration nor solenoid field
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