Performance and Programmability of MPI+X Integration with CUDA, HIP, SYCL, OpenACC, and OpenMP Offloading for Supercomputing: A Case Study on Dense Matrix?Vector Multiplication - Krishnasamy, Ezhilmathi; Throtter, James; Cai, Xing; Pleiter, Dirk; Kos, Leon; Saavedra, Laura; Bouvry, Pascal (Proceedings Of The Supercomputing Asia And International Conference On High Performance Computing In Asia Pacific Region Workshops, 2026)