An NLO-matched initial and final state parton shower on a GPU

Recent developments have demonstrated the potential for high simulation speeds and reduced energy consumption by porting Monte Carlo Event Generators to GPUs. We release version 2 of the CUDA C++ parton shower event generator GAPS, which can simulate initial and final state emissions on a GPU and is capable of hard-process matching. As before, we accompany the generator with a near-identical C++ generator to run simulations on single-core and multi-core CPUs. Using these programs, we simulate NLO Z production at the LHC and demonstrate that the speed and energy consumption of an NVIDIA V100 GPU are on par with a 96-core cluster composed of two Intel Xeon Gold 5220R Processors, providing a potential alternative to cluster computing.