Accelerating the Calculation of Scattering of Complex Targets from Background Radiation with CUDA, OpenACC and OpenHMPP

Graphics Processing Unit (GPU) is used to accelerate the calculation of scattering of complex target from background radiation in infrared spectrum. Compute Unified Device Architecture (CUDA), OpenACC, and Hybrid Multicore Parallel Programming (OpenHMPP) implementations are presented. In all our implementation, scattering of background radiation in different directions are calculated in parallel. A personal desktop with 2 NVIDIA GTX GeForce 590 with an Intel i7 CPU is used in our experiment. In CUDA, by using shared memory to buffer the background radiation and BRDF parameters and tuning the grid organization, we achieve a speedup of 197x. OpenACC implementation is realized by inserting the parallel loop construct with reduction clause before the loop in original serial code. By utilization of data clause and tuning number of gangs used, a speedup of 158.9x is obtained. In OpenHMPP implementation, the loop iterating over incident direction of original code is transformed to the codelet function and we achieve a speedup of 160.7x. Our effort makes the calculation of complex target in real time possible.