ADASS XIII conference proceedings article:
AAS 203rd Meeting, January 2004
[4.01] QLWFPC2: Parallel-Processing Quick-Look WFPC2 Stellar Photometry based on the Message Passing Interface
K. J. Mighell (National Optical Astronomy Observatory)
I describe a new parallel-processing stellar photometry code
called QLWFPC2 which is designed to do quick-look analysis
of two entire WFPC2 observations from the Hubble Space
Telescope in under 5 seconds using a fast Beowulf cluster
with a Gigabit Ethernet local network. This program is
written in ANSI/ISO C and uses the MPICH implementation of
the Message Passing Interface from the Argonne National
Laboratory for the parallel-processing communications, the
CFITSIO library (from HEASARC at NASA's GSFC) for reading
the standard FITS files from the HST Data Archive and the
Parameter Interface Library (from the INTEGRAL Science Data
Center) for the IRAF parameter-file user interface. QLWFPC2
running on 4 processors takes about 2.4 seconds to analyze
WFPC2 archive datasets u37ga407r.c0.fits (F555W; 300 s) and
u37ga401r.c0.fits (F814W; 300 s) of M54 (NGC 6715) which is
the bright massive globular cluster near the center of the
nearby Sagittarius dwarf spheroidal galaxy. The analysis of
these HST observations of M54 lead to the serendipitous
discovery of more than 50 new bright variable stars in the
central region of M54. Most of the candidate variables stars
are found on the PC1 images of the cluster center --- a
region where no variables have been reported by previous
ground-based studies of variables in M54. This discovery is
an example of how QLWFPC2 can be used to quickly explore the
time domain of observations in the HST Data Archive. This
work is supported by a grant from the National Aeronautics
and Space Administration (NASA), Order No. S-13811-G, which
was awarded by the Applied Information Systems Research
Program (AISRP) of NASA's Office of Space Science (NRA
01-OSS-01).
If you would like more information about this abstract, please
follow the link to http://www.noao.edu/staff/mighell/qlwfpc2.
203rd AAS meeting poster:
QLWFPC2 release:
2005OCT28
Retrieve and build MX
Build QLWFPC2:
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More to come...
Figure 1.
Typical QLWFPC2 performance results with two entire WFPC2 observations
of a Local Group globular cluster running on a 5-node Beowulf cluster
with 1.8 GHz CPUs connect with Gigabit Ethernet. The
blue points
show actural run times for 1 to 5 processors.
The thin line shows a simple performance model
based on measure cluster performance metrics (network bandwidth,
disk I/O bandwidth, and performace with a single CPU).
The thick line shows the theoretical limit of
performance based on the system performace metrics.
Note that the current version of QLWFPC2 already meets the ideal performance
values for 1, 2, and 4 processors.
QLWFPC2 running on 4 processors takes about 2.4 secons
to anlyze the WFPC2 archive data
sets u37ga407r.c0.fits (F555w; 300 s)
and u37ga401r.c0.fits (F814w; 300 s)
of M54 which is the bright massive globular cluster near the
center of the nearby Sagittarius dwarf spheroidal galaxy.
QLWFPC2 analyzed over 50,000 point source candidates and
reported V, I, F555W, and F814W photometry of 14,611 stars
with signal-to-noise ratios of 8 or better.
Session 4 Computation, Data Handling and Image Analysis
Poster, Monday, January 5, 2004, 9:20am-6:30pm, Grand Hall
(^ click on this link and follow the instructions)
Kenneth Mighell
Associate Scientist
Kitt Peak National Observatory
National Optical Astronomy Observatory
EMAIL: mighell at noao dot edu
MAIL: P.O. Box 26732, Tucson, AZ 85726-6732
FEDEX: 950 N. Cherry Ave., Tucson, AZ 85719
PHONE: (520) 318-8391
FAX: (520) 318-8360
URL: http://www.noao.edu/staff/mighell/
Updated:
2005 November 09 @ 17:04 MST