A GPU-based correlator X-engine implemented on the CHIME Pathfinder. - Nolan Denman; Mandana Amiri; Kevin Bandura; Liam Connor; Matt Dobbs; Mateus Fandino; Mark Halpern; Adam D. Hincks; Gary Hinshaw; Carolin Höfer; Peter Klages; Kiyoshi Masui; et al. (ASAP, 2015)