The SFXC software correlator for Very Long Baseline Interferometry: Algorithms and Implementation

TL;DR

This paper describes the design, implementation, and performance of the SFXC software correlator for VLBI, highlighting its novel modes like wide-field imaging and pulsar gating, and providing detailed algorithmic and architectural insights.

Contribution

It introduces the SFXC software correlator, detailing its algorithms, architecture, and novel modes, demonstrating its scalability and performance on Linux clusters.

Findings

Efficient correlation performance scales with CPU cores and spectral channels.

Enables wide-field VLBI imaging through multiple phase centers.

Supports pulsar gating and binning modes.

Abstract

In this paper a description is given of the SFXC software correlator, developed and maintained at the Joint Institute for VLBI in Europe (JIVE). The software is designed to run on generic Linux-based computing clusters. The correlation algorithm is explained in detail, as are some of the novel modes that software correlation has enabled, such as wide-field VLBI imaging through the use of multiple phase centres and pulsar gating and binning. This is followed by an overview of the software architecture. Finally, the performance of the correlator as a function of number of CPU cores, telescopes and spectral channels is shown.