Highlighted notes on:
Parallel algorithms for multi-source graph traversal and its applications.
While doing research work with Prof. Kishore Kothapalli.
Seema is working on Multi-source BFS with hybrid-CSR, with applications in APSP, diameter, centrality, reachability.
BFS can be either top-down (from visited nodes, mark next frontier), or bottom-up (from unvisited nodes, mark next frontier). She mentioned that hybrid approach is more efficient. EtaGraph uses unified degree cut (UDC) graph partitioning. Also overlaps data transfer with kernel execution. iCENTRAL uses biconnected components for betwenness centrality on dynamic graphs.
Hybrid CSR uses an additional value array for storing packed "has edge/neighbour" bits. This can give better memory access pattern if many bits are set, and cause many threads to wait if many bits are zero. She mentioned Volta architecture has independent PC, stack per thread (similar to CPU?). Does is not matter then if the threads in a block diverge?
(BFS = G*v, Multi-source BFS = G*vs)