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AFS
Development Host Filesystem

Integrated Development Environments

Not a good idea to prescribe these for everyone. Three good open source choices for our technology stack are emacs+jdee, Netbeans (including matisse) and the Eclipse IDE. All three include CVS integration.

RED FLAGS

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. So, if plane coupled orbit correction is important for us, we need to add at least 4x4 and probably 6x6 tracking.

XAL Modelled acceleration and solenoid. XAL does not model acceleration (required for ???) nor solenoid field (required for ???). These have to be added.

Archiver.
REQUIRED ADDITIONS TO SLC CONTROL SYSTEM

An LCLS model beamline, associated sectors and db additions in support of it, must be added.

Pulse-id acquisition by Correlation Plots. Presently broken needs to be fixed.

REQUIRED SOLUTIONS

This section lists functional components of the LCLS modeling applications architecture which for which we need to decide on a vendor:

1. Numerical Analysis package, for matrix manipulation and linear algebra. Some classes of XAL extend JAMA 4, this may be sufficient.
2. J2EE compliant Application Server. Application Servers include technology for accessing databases (eg oracle) and displaying information to the web. This will be useful for displaying static control data, model information and other slow control configs etc, to the web and to the Integrated Control Program. Suggest Apache Jakarta, plus PHP, Xerces, Xalan, etc.

JOB LIST

SQL script and other munging to get from Oracle db description of geometry and devices to a lattice description in an XAL input file.

The XAL tracker. An XAL application which tracks the lattice and produces a 2nd XAL file containing the twiss parameters for each device, plus other per-element parameters see Test page.

Check XAL's linear algebra support. Done: it uses JAMA -see ref.

XAL tracking. To add acceleration and solenoid elements to XAL.

Create a Skills Matrix for applications, eg, XML and associated technologies (DOM, XSL etc), Oracle and associated technologies (SQL, PHP, persistence).

QUESTIONS

Does XAL really not model acceleration? If not how is it useful for SNS?

Verify that XAL does not model a plane coupled system.

Does XAL offer matrix manipulation, linear algebra and fitting adequate for the LCLS? Ans: yes, uses JAMA.

How long does XAL take to parse an XAL beamline? It has to build a DOM tree, which can't be negligible. Since that is a requirement of every XAL application at initialization its an important performance bottleneck.

Does LCLS need SVD based orbit minimization? Is there an orbit minimization in XAL?

R&D

Matlab

Specifically: Do AT applications appear to offer support for configurations necessary in a large machine (e.g. choosing from available bpms and correctors in an orbit correction package). How does it handle errors? Are bpm statuses communicated to the user interface and graphics?

Can Matlab be used as a general purpose charting engine? This would be very much more desirable than XAL's charting if having charted the data for a plot one could easily "drop into matlab" to further analyse the data just plotted.

Should the production executables (XAL java jar files etc) and configuration files be on AFS or NFS? Operative points in the question are that both XAL and Eclipse require that the user specify a "workspace" at startup, which defines their particular configuration. This workspace must always be writable, so AFS token expiry after 25 hrs use, can be problematic. Simplest solution is makefile "install" to a mounted NFS directory - but that directory has to be accessible by all head nodes (that is, all linux desktops running the applications).

Eclipse includes two software distribution mechanisms: first requires "pull" (the user initiates the update), 2nd is Java Web Start, which checks for updates at predefined intervals.

DETAILS

A programmer spends half their time handling errors, so making that as easy as possible is a productivity priority. For LCLS we will use the following technology stack:

Err. Err makes the process of rigorously handling errors easy. It allows a programmer to define an error code in a structured, recorded global way; and to use that code to issue errors and associated diagnostics from or linux, solaris, windows platforms in either java or C/C++, and issue them directly to CMLOG (or some other message logger). It includes support for exception chaining ("caused-by") and exception translation, so the end user can see what systematic thing caused their functional problem (E.g. of a error logged by Err in cmlog might be "UnableToTrackBeamlineException: LCLS ; caused by FileNotFoundException: LCLS.XML when attempting to steer LCLS".

Cmlog. cmlog is a message logger that can be used for error messages. It includes components for receiving messages to log from programs running on the network (either in hosts or IOCs), logging those errors in a database, and a viewer for browsing the logged messges.

jcmlog. jcmlog is a sophisticated error log viewer for CMLOG developed at SLAC recently for LCLS. It is in general much faster and smother than the nominal CMLOG viewer from Jlab and includes facilities for handling the particular requirements of Err (above) such as horizontal scroll for long messages.

NAMES

LIPS LCLS integrated physics system
SIPS SLAC integrated/interactive physics system
iSCP Integrated SLAC Control System
SOMA SLAC online modeling applications.

TECHNOLOGY GLOSSARY

#Oracle: The enterprise db contains static data on devices and their beamline geometry.
#XAL: Existing software which contains a lattice tracker, java bean classes for programs to deal with accelerator devices in an object oriented way, and code for building GUI applications based on Swing.
#XML (see references): A computer language for writing files containing structured data. XML is used by XAL as the language of its input model files. Data in XML is trivially transformed via XSL into other forms, such as HTML for easy display on the web, or other XML files suitable for other programs or putting into a db.
#AIDA (Accelerator Independent Data Access), a Java API to EPICS Channel Access, SLC database device data, BPM and magnet data and control, EPICS and SLC history data, SLC modeling data.

1. Err - a platform and language independent (java & c++) error handling framework for creating and logging error messages.
   #global message: error or warning text message typically going to some log like cmlog, and viewed by a user through a browser like cmlog browser. A global message is on generated by a front-end computer or an application that thinks it's worth telling the world about. compare to local message
   #local message: a message generated by an application that is intended only for viewing by the application's user at that time. Eg "0 is not a permitted number of iterations to average bpm readings".

REFERENCES

1 http://www.sns.gov/APGroup/appProg/xal/xal.htm^{Image Added}
2 XML, http://en.wikipedia.org/wiki/XML^{Image Added}
3 LCLS lattice files.
4 JAMA, http://math.nist.gov/javanumerics/jama/^{Image Added}

To do
Add gold lattice to optics flowchart diagram