PPPL Spring/Summer CO-OP 2006

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PPPL Spring/Summer CO-OP 2006
Stephen Krenzel
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Focus of the CO-OP

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

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Original ElVis Architecture
ElVis
Application or Applet
Initially, rplot sent data directly to ElVis, or
data was read from the local file system.
Application or Applet
File-System
Commands rplot text
Network
rplot elvis_server elvis_port
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ElVis Portal Architecture
ElVis
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.
Application or Applet
Application or Applet
Commands rplot text
File-System
Commands rplot text
Network
rplot elvis_server elvis_port
Rplot text
stdio
ElVis Servlet
clterm pty
Graph Window Handler
xml data
Elvis API
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Areas of Attention

• XML Protocol for ElVis API
• Logarithmic Plotting
• Whiteboard
• Development Process

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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

ltmemo date02/19/99gt lttogtPeterlt/togt ltfromgtBill
lt/fromgt ltheadinggtReminderlt/headinggt ltmessagegt
Don't forget to put the new coversheet on the
TPS reports. lt/messagegt lt/memogt
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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, 2.4.21
  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.

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Simple EML Example

• lt?xml version'1.0' encoding'utf-8'?gt
• ltvisualstategt
• ltgraphwindowgt
• ltgraph title"test"gt
• ltaxis text"X" direction"x"/gt
• ltaxis text"Y" direction"y"/gt
• ltdata1d name"data"gt
• ltpoint x"0" y"0"/gt
• ltpoint x"1" y"2"/gt
• ltpoint x"2" y"4"/gt
• lt/data1dgt
• lt/graphgt
• lt/graphwindowgt
• lt/visualstategt

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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

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Log axis class used in surface plots.
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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

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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

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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.
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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

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Summary

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

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Thank You

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