Data Optimization for Reflectometer Simulation

Marc Osherson

Science Education Summer Intern

9/1/2005

FWR A 2D simulation of a full wave reflectometer for

which Eliot Feibush has been developing a GUI. Client-server architecture.

GUI can run on a user’s laptop. Input and Output netCDF files are on the PPPL cluster. Files had to be transferred to the laptop, and processed there.

PPPL Compute Cluster

User’s PC, Mac, Linux

Multi – Tier Software Architecture

Java Client GUI Java Servlet

FWR Simulation

TRANSP

genxpl

trxplnetCDF Files

MDSplus Server

TRANSP Runs

Correlation

Graphs

FWR Input

FWR Solution

netCDFcon

Problem Input and output files became prohibitively large

for laptops, e.g. 100MB output files. The files would take too long to transfer and

process. The Java heap memory was too small and could not

handle such files.

Approach Server side post-processing of input and output

files. Reduce simulation data to just the displayable

image data. Arrays of doubles converted to byte data.

Provide a means for recovering the actual data values.

netCDFcon (C program) Converts the plasma input file into efficient image data.

Computes the three cutoff images and scales them into image data.

Converts the full wave solution file to image data. Runs on the PPPL compute server, much faster than running

Java on a laptop. Roughly 100:1 speed up.

Converts a 100MB solution file to 1MB. Significantly reduces file transfer time.

Convert once, display many times.

netCDFcon Linux command line program. Command line arguments:

Input file Output file Type of processing List of variables, e.g. ne te bb

Run by the servlet in a script file.

FWR Screenshots

Reflectometer Simulation

FWR Demo

FWR Demo

Questions ?

Thank you To the entire science education staff for making this

possible. To Eliot Feibush for all the help he’s given me. To PPPL for this opportunity.