3,434 research outputs found
Inner product computation for sparse iterative solvers on\ud distributed supercomputer
Recent years have witnessed that iterative Krylov methods without re-designing are not suitable for distribute supercomputers because of intensive global communications. It is well accepted that re-engineering Krylov methods for prescribed computer architecture is necessary and important to achieve higher performance and scalability. The paper focuses on simple and practical ways to re-organize Krylov methods and improve their performance for current heterogeneous distributed supercomputers. In construct with most of current software development of Krylov methods which usually focuses on efficient matrix vector multiplications, the paper focuses on the way to compute inner products on supercomputers and explains why inner product computation on current heterogeneous distributed supercomputers is crucial for scalable Krylov methods. Communication complexity analysis shows that how the inner product computation can be the bottleneck of performance of (inner) product-type iterative solvers on distributed supercomputers due to global communications. Principles of reducing such global communications are discussed. The importance of minimizing communications is demonstrated by experiments using up to 900 processors. The experiments were carried on a Dawning 5000A, one of the fastest and earliest heterogeneous supercomputers in the world. Both the analysis and experiments indicates that inner product computation is very likely to be the most challenging kernel for inner product-based iterative solvers to achieve exascale
Beyond 5G Networks: Integration of Communication, Computing, Caching, and Control
In recent years, the exponential proliferation of smart devices with their
intelligent applications poses severe challenges on conventional cellular
networks. Such challenges can be potentially overcome by integrating
communication, computing, caching, and control (i4C) technologies. In this
survey, we first give a snapshot of different aspects of the i4C, comprising
background, motivation, leading technological enablers, potential applications,
and use cases. Next, we describe different models of communication, computing,
caching, and control (4C) to lay the foundation of the integration approach. We
review current state-of-the-art research efforts related to the i4C, focusing
on recent trends of both conventional and artificial intelligence (AI)-based
integration approaches. We also highlight the need for intelligence in
resources integration. Then, we discuss integration of sensing and
communication (ISAC) and classify the integration approaches into various
classes. Finally, we propose open challenges and present future research
directions for beyond 5G networks, such as 6G.Comment: This article has been accepted for inclusion in a future issue of
China Communications Journal in IEEE Xplor
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