PPPL Spring/Summer CO-OP 2006 Stephen Krenzel

Focus of the CO-OP The co-op focused on improving ElVis, an application for the visualization and monitoring of scientific data.

Application or Applet Commands rplot text Original ElVis Architecture Initially, rplot sent data directly to ElVis, or data was read from the local file system. ElVis File-System rplot elvis_server elvis_port Application or Applet Network

Application or Applet Commands rplot text ElVis Portal Architecture ElVis is moving to a services oriented architecture. ElVis can now acquire data through a compute service. This allows ElVis to run effectively as an applet in a web browser or as a stand-alone application. It also supports collaboration between users. Many of ElVis' design decisions are now centered around constraints imposed by applets. ElVis File-System ElVis Servlet Graph Window Handler clterm pty rplot elvis_server elvis_port Elvis API Commands rplot text Rplot text stdio Application or Applet xml data Network

Areas of Attention ➢ XML Protocol for ElVis API ➢ Logarithmic Plotting ➢ Whiteboard ➢ Development Process

XML File Format ➢ XML (eXtensible Markup Language) is a general purpose markup language for describing structured information. ➢ Human-readable, yet easily handled by machines ➢ Self-documenting and widely supported ➢ Example: Peter Bill Reminder Don't forget to put the new coversheet on the TPS reports.

EML (ElVis Markup Language) ➢ Old format: ➢ Proprietary binary byte-stream ➢ Many compatibility and versioning issues ➢ New XML based format: ➢ Implemented using open industry standards, and a robust framework (dom4j) ➢ Easily extended, and important to ElVis moving forward ➢ Formally specified in a Document Type Definition (DTD) ➢ allows others to easily adopt the format ➢ Network transparent and backward compatible ➢ Speed: ~70,000 data points / second ➢ (SUN Java 1.4.2_11, Intel Xeon 3.00Ghz, Linux kernel ) ➢ Size: XML is verbose, however has very high compressions ratios if size becomes a problem. Typically on the order of 91% - 99% in tests done on EML files.

Simple EML Example

Logarithmic Plotting ➢ ElVis now supports viewing data linearly or logarithmically on either axis ➢ Applies to single or multi-variable data ➢ Translating and scaling of logarithmic axes are still in progress ➢ Tested to work with rplot and sigtab ➢ The classes were also utilized by Tarun Pondicherry in his work with logarithmic surface plots

Log axis class used in surface plots.

Whiteboard ➢ Users can now draw arrows, circles, rectangles, lines, and freestyle ➢ Anything that can be drawn, including highlights on data, can have its color, thickness and style set ➢ Objects can now be selected, translated, removed, and have attributes modified after being drawn ➢ Highlights on indexed data persist as the data is animated, allowing areas of interest to remain marked ➢ Whiteboard objects are now saved and read from NetCDF files

Development Process ➢ Introduced the Eclipse integrated development environment (IDE) ➢ Facilitates team oriented development through tight integration with CVS ➢ Iterative compiler ➢ Code changes are applied in real-time ➢ This is particularly useful when setting up test cases ➢ Has easy to use debugging utilities ➢ Intelligent code handling and general “awareness” of potential issues ➢ Some support for other languages as well

Using the eclipse debugger was invaluable for debugging image display code. This is another java client for the reflectometer. Three images, each at different resolutions, overlapping.

Development Process ➢ Some code was optimized by removing instances of unnecessary code ➢ i.e. methods being called to update values that hadn't been changed ➢ Assisted by Eclipse's code analysis tools, over 550 warnings, bugs, and miscellaneous fixes (i.e. unused code) were made

Summary ➢ Enhancements to ElVis Architecture ➢ Log Plotting ➢ Whiteboard ➢ Software Development Environment (Teach a man to fish...)

Thank You In particular, I'd like to thank Eliot Feibush, Doug McCune, Drexel University and the Princeton Plasma Physics Lab.