Teraflop per second gravitational lensing ray-shooting using graphics processing units

TL;DR

This paper demonstrates a highly efficient GPU-based implementation of gravitational lensing ray-shooting, achieving teraflop performance and enabling billion-lens microlensing simulations on a single machine within a day.

Contribution

The authors develop a GPU-accelerated inverse ray-shooting method for gravitational lensing, achieving unprecedented performance and scalability with multiple GPUs.

Findings

Single GPU achieves 182 Gflop/s performance.

Multi-GPU system reaches 1.28 Tflop/s.

Billion-lens microlensing simulations completed in about a day.

Abstract

Gravitational lensing calculation using a direct inverse ray-shooting approach is a computationally expensive way to determine magnification maps, caustic patterns, and light-curves (e.g. as a function of source profile and size). However, as an easily parallelisable calculation, gravitational ray-shooting can be accelerated using programmable graphics processing units (GPUs). We present our implementation of inverse ray-shooting for the NVIDIA G80 generation of graphics processors using the NVIDIA Compute Unified Device Architecture (CUDA) software development kit. We also extend our code to multiple-GPU systems, including a 4-GPU NVIDIA S1070 Tesla unit. We achieve sustained processing performance of 182 Gflop/s on a single GPU, and 1.28 Tflop/s using the Tesla unit. We demonstrate that billion-lens microlensing simulations can be run on a single computer with a Tesla unit in timescales of order a day without the use of a hierarchical tree code.