Architecture, implementation and parallelization of the software to search for periodic gravitational wave signals

The parallelization, design and scalability of the PolGrawAllSky code to search for periodic gravitational waves from rotating neutron stars is discussed. The code is based on an efficient implementation of the FF-statistic using the Fast Fourier Transform algorithm. To perform an analysis of data from the advanced LIGO and Virgo gravitational wave detectors’ network, which will start operating in 2015, hundreds of millions of CPU hours will be required—the code utilizing the potential of massively parallel supercomputers is therefore mandatory. We have parallelized the code using the Message Passing Interface standard, implemented a mechanism for combining the searches at different sky-positions and frequency bands into one extremely scalable program. The parallel I/O interface is used to escape bottlenecks, when writing the generated data into file system. This allowed to develop a highly scalable computation code, which would enable the data analysis at large scales on acceptable time scales. Benchmarking of the code on a Cray XE6 system was performed to show efficiency of our parallelization concept and to demonstrate scaling up to 50 thousand cores in parallel.Program summaryProgram title: parallel PolGrawAllSkyCatalogue identifier: AEUX_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEUX_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 163747No. of bytes in distributed program, including test data, etc.: 28989030Distribution format: tar.gzProgramming language: C.Computer: Any parallel computing platform supporting MPI standard.Operating system: Linux as well any other supporting MPI standard.Has the code been vectorized or parallelized?: Yes, using MPI. Tested with up to 50208 processorsRAM: 1 Gigabyte per parallel taskClassification: 1.5.External routines: MPI v.2 or newer, FFTW v.3 or newerNature of problem:Search for periodic gravitational waves from rotating neutron stars.Solution method:The FF-statistic method using the Fast Fourier Transform algorithm.Running time:The example provided takes approximately 30 mins with 256 processors.