PPPL Spring/Summer CO-OP 2006Stephen 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_serverelvis_port

Application or Applet

Network

Application or Applet

Commands

rplot text

ElVis Portal ArchitectureElVis 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 betweenusers. Many of ElVis' design decisions are now centered around constraints imposed by applets.

ElVis

File-System

ElVis Servlet

Graph WindowHandler

cltermpty

rplot

elvis_serverelvis_port

Elvis API

Commands

rplot text

Rplottext

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:

<memo date=”02/19/99”><to>Peter</to><from>Bill</from><heading>Reminder</heading><message>

Don't forget to put the newcoversheet on the TPS reports.

</message></memo>

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.

Simple EML Example• <?xml version='1.0' encoding='utf-8'?>

• <visualstate>

• <graphwindow>

• <graph title="test">

• <axis text="X" direction="x"/>

• <axis text="Y" direction="y"/>

• <data1d name="data">

• <point x="0" y="0"/>

• <point x="1" y="2"/>

• <point x="2" y="4"/>

• </data1d>

• </graph>

• </graphwindow>

• </visualstate>

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 differentresolutions, 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.