A GPU Implementation of Extragalactic Radio Source Detection A CUDA Approach
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Transcript of A GPU Implementation of Extragalactic Radio Source Detection A CUDA Approach
A GPU Implementation of Extragalactic Radio Source Detection
A CUDA Approach
Gary Resnick Scott Badenhorst
Department of Computer ScienceUniversity of Cape Town
17 March, 2010
Introduction
Approach
Plan
Outcomes
Overview
Radio Astronomy
A radio image of the sky
Radio Interferometry
What is a Source?
PipelineTelescope Array
Correlation
Converting to frequency space
Cleaning the dirty map
Source Extraction
Source Extraction
Source Extraction PipelineReading in the data
Compute Threshold
Apply threshold
Blob detection
Generate Catalogue
FITS Data Cube
Blob Detection (XY)
Characterisation (Z)
HI (Neutral Hydrogen)
AIPS◦ IMFIT◦ IMSAD
Source Extractor◦ Deblend
Duchamp◦ Own variation
Related Work
PlanBack down to Earth
Can the GPU be utilized for efficient image source extraction?
How well does a GPU solution scale
to handle large image data volumes?
Can we improve the processing time of current source extraction software?
Research Questions
The accuracy of the GPU implementations are greater than or equate to current extraction algorithms ◦ Sufficient reliability of faint source detection
Spurious detections (Type I error) are constrained by a p-value of 0.05
Attaining a speedup on the GPU implementations in the order of 10x or greater than traditional CPU implementations
Key Success Factors
Work Allocation
Input Handling• L
ogical segmentation of data cube
Thresholding• D
etermine a threshold cut-off value
Source Extraction• C
PU (Serial) & GPU (Parallel) Blob detection
Validation & Filtration• S
plit/merge sources and check errors
Catalogue Generation• C
alculate source parameters (velocity, position, etc) and create listing
TeamIndividually
Each member will independently implement a CPU implementation of a source extraction algorithm and then port it to the GPU
Source Extraction
Gary
•Duchamp• GPU
Scott
•SeXtractor• GPU
Interfaces with Framework
Source Extraction
Segments (grids) of pixels
List of sources
Validation & Filtration
Validated source list
Factor Probability Impact RiskFailure to acquire data low low lowStakeholder departure low high lowData/code loss low high mediu
mUnsuccessful module implementation medium mediu
mmedium
Hardware failure low medium
high
Cascading delay medium high medium
Risks
Risk Factors
Radio Survey Data◦ Synthesized◦ Real Sky Map
Implemented in C/C++ & CUDA on GNU/Linux◦ CFITSIO & WCSLIB Libraries
Developed on NVIDIA (CUDA Compliant) Fermi architecture◦ High-end machine with current gen NVIDIA card(s)
People
Resources Required
Outcomes
Software developed for source extraction and catalogue generation.
Two independent reports A website and poster Presentation to demonstrate the
project.
Deliverables & Milestones
Open Source◦ Distributed under GNU GPL
Akin to Duchamp & SeXtractor GNU/Linux Compatibility
◦ Comparable performance/accuracy across distros Institutions maintain data ownership
◦ Retains rights to catalogues produced Data Integrity
◦ Standardized input and output formats
Ethical, Professional & Legal Issues
We present an approach to solving a problem within Astronomy that needs to be addressed
Our approach is well thought out and relevant
A balanced and fair work load has been allocated to each member
The project has minimal unmitigated risks
Conclusion
Questions?
Project Timeline