GRay: a Massively Parallel GPU-Based Code for Ray Tracing in Relativistic Spacetimes

Understand

We introduce GRay, a massively parallel integrator designed to trace the trajectories of billions of photons in a curved spacetime.

• This GPU-based integrator employs the stream processing paradigm, is implemented in CUDA C/C++, and runs on nVidia graphics cards.
• The peak performance of GRay using single precision floating-point arithmetic on a single GPU exceeds 300 GFLOP (or 1 nanosecond per photon per time step).
• For a realistic problem, where the peak performance cannot be reached, GRay is two orders of magnitude faster than existing CPU-based ray tracing codes.