2015/03/20 by Peter Klages, Klages, Peter, Kevin Bandura +9
Engineering · Physics and Astronomy · #FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Microwave Engineering and Waveguides #Radio Astronomy Observations and Technology #Superconducting and THz Device Technology
paper · pdf · doi:10.48550/arxiv.1503.06203
openalex publication_date 2015/03/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Interferometric radio telescopes often rely on computationally expensive O(N2) correlation calculations; fortunately these computations map well to massively parallel accelerators such as low-cost GPUs. This paper describes the OpenCL kernels developed for the GPU based X-engine of a new hybrid FX correlator. Channelized data from the F-engine is supplied to the GPUs as 4-bit, offset-encoded real and imaginary integers. Because of the low bit width of the data, two values may be packed into a 32-bit register, allowing multiplication and addition of more than one value with a single fused multiply-add instruction. With this data and calculation packing scheme, as many as 5.6 effective tera-operations per second (TOPS) can be executed on a 4.3 TOPS GPU. The kernel design allows correlations to scale to large numbers of input elements, limited only by maximum buffer sizes on the GPU. This code is currently working on-sky with the CHIME Pathfinder Correlator in BC, Canada.