Kokkos Kernel: streams interfaces of spiluk and sptrsv

[lucbv]

Description of the new ILU(K) preconditioner running on multiple streams using partitioned execution space instances.

[vqd8a]

Due to miscommunication, this talk was presented together with #83 on Monday Dec-12 (sorry for that)
Here is the presentation KokkosKernels_StreamInterface_SpILUK_SpTRSV_KUG2023_v2.pptx

Abstract: Sparse incomplete LU factorization (ILU) and sparse triangular solvers have been widely used as preconditioner in iterative solution algorithms. Kokkos Kernels has provided two kernels SPILUK and SPTRSV for incomplete LU factorization and triangular solve, respectively. These kernels were integrated into Trilinos Ifpack2's preconditioner RILUK and Ifpack2's local triangular solver. Although SPILUK and SPTRSV are robust but it is hard to achieve good parallelism due to the fact that these are based upon algorithms that are inherently sequential. In this talk, we will introduce a new feature which has been released recently in Kokkos Kernels. We focus on implementing less expensive SPILUK and SPTRSV kernels on GPUs using stream executions.