15 July 2008 CRBLASTER: a fast parallel-processing program for cosmic ray rejection
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Many astronomical image-analysis programs are based on algorithms that can be described as being embarrassingly parallel, where the analysis of one subimage generally does not affect the analysis of another subimage. Yet few parallel-processing astrophysical image-analysis programs exist that can easily take full advantage of todays fast multi-core servers costing a few thousands of dollars. A major reason for the shortage of state-of-the-art parallel-processing astrophysical image-analysis codes is that the writing of parallel codes has been perceived to be difficult. I describe a new fast parallel-processing image-analysis program called crblaster which does cosmic ray rejection using van Dokkum's L.A.Cosmic algorithm. crblaster is written in C using the industry standard Message Passing Interface (MPI) library. Processing a single 800×800 HST WFPC2 image takes 1.87 seconds using 4 processes on an Apple Xserve with two dual-core 3.0-GHz Intel Xeons; the efficiency of the program running with the 4 processors is 82%. The code can be used as a software framework for easy development of parallel-processing image-anlaysis programs using embarrassing parallel algorithms; the biggest required modification is the replacement of the core image processing function with an alternative image-analysis function based on a single-processor algorithm. I describe the design, implementation and performance of the program.
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Kenneth J. Mighell, Kenneth J. Mighell, } "CRBLASTER: a fast parallel-processing program for cosmic ray rejection", Proc. SPIE 7019, Advanced Software and Control for Astronomy II, 70191F (15 July 2008); doi: 10.1117/12.789611; https://doi.org/10.1117/12.789611

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