{"685916":{"#nid":"685916","#data":{"type":"event","title":"School of CSE Seminar Series: Andreas Stathopoulos","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003ESpeaker:\u003C\/strong\u003E\u0026nbsp;Andreas Stathopoulos, professor at College of William \u0026amp; Mary\u003Cbr\u003E\u003Cstrong\u003EDate and Time:\u003C\/strong\u003E\u0026nbsp;October 24, 2:00-3:00 p.m.\u003Cbr\u003E\u003Cstrong\u003ELocation:\u003C\/strong\u003E\u0026nbsp;Coda, Room 114\u003Cbr\u003E\u003Cstrong\u003EHost:\u003C\/strong\u003E\u0026nbsp;Edmond Chow\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ETitle:\u003C\/strong\u003E\u0026nbsp;\u003Cem\u003EImproving and Evaluating Streaming SVD for Large Scale Problems\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAbstract:\u003C\/strong\u003E We study streaming singular value decomposition (SVD) for approximating large-scale SVD problems where data matrices are too large to store or recompute. Our focus is on Incremental SVD (iSVD), which applies hard-thresholding truncation after each streamed window. In contrast, Frequent Directions employs soft thresholding with provable but often loose bounds, and randomized methods such as SketchySVD construct one-pass sketches. \u0026nbsp;We propose algorithmic and theoretical improvements to iSVD and evaluate them experimentally. \u0026nbsp;\u003C\/p\u003E\u003Cp\u003EA \u201clarge-window\u201d variant processes as many rows as memory allows, improving both accuracy and efficiency. Implemented in Skema, a high-performance C++ framework using Kokkos and PRIMME, this approach scales to massive datasets. Algorithmic contributions include warm-start iterative solvers reducing iterations by 30\u201350% and a reservoir-sampling\u2013based convergence criterion for early stopping.\u003C\/p\u003E\u003Cp\u003ETheoretically, we outline a proof roadmap that when streaming rows in a random order (random shuffle), iSVD avoids pathological cases and achieves higher expected accuracy than Frequent Directions. Complexity analysis clarifies accuracy\u2013cost trade-offs with SketchySVD, while experiments demonstrate that iSVD achieves several orders of magnitude higher accuracy at competitive runtime. As an application, we use iSVD to obtain better quality multigrid prolongators in Lattice Quantum Chromodynamics.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EBio:\u003C\/strong\u003E Andreas Stathopoulos is a Professor of Computer Science at William \u0026amp; Mary in Virginia, USA. He was awarded an NSF CISE Postdoctoral Fellowship after receiving his Ph.D. and M.S. in Computer Science from Vanderbilt University; he also completed a B.S. in Mathematics from the University of Athens in Greece. Dr. Stathopoulos\u2019 research interests include numerical analysis and high performance computing; methods for large eigenvalue problems and linear systems of equations; and related applications from materials science and quantum chromodynamics. He co-developed PRIMME (Preconditioned Iterative MultiMethod Eigensolver), one of the foremost eigenvalue packages, several other significant software tools, and has published numerous journal articles and conference papers in computational sciences and applications. \u0026nbsp;He is a member of IEEE, IEEE Computer, and SIAM. Since 2010 he is an Associate Editor in SIAM Journal on Scientific Computing and from 2016-2022 served as its Section Editor for Software and HPC.\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cstrong\u003ESpeaker:\u003C\/strong\u003E\u0026nbsp;Andreas Stathopoulos, professor at College of William \u0026amp; Mary\u003Cbr\u003E\u003Cstrong\u003EDate and Time:\u003C\/strong\u003E\u0026nbsp;October 24, 2:00-3:00 p.m.\u003Cbr\u003E\u003Cstrong\u003ELocation:\u003C\/strong\u003E\u0026nbsp;Coda, Room 114\u003Cbr\u003E\u003Cstrong\u003EHost:\u003C\/strong\u003E\u0026nbsp;Edmond Chow\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ETitle:\u003C\/strong\u003E\u0026nbsp;\u003Cem\u003EImproving and Evaluating Streaming SVD for Large Scale Problems\u003C\/em\u003E\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"School of CSE hosts a seminar from College of William \u0026 Mary Professor Andreas Stathopoulos"}],"uid":"36319","created_gmt":"2025-10-22 15:56:21","changed_gmt":"2025-10-22 16:53:00","author":"Bryant Wine","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-10-24T14:00:00-04:00","event_time_end":"2025-10-24T15:00:00-04:00","event_time_end_last":"2025-10-24T15:00:00-04:00","gmt_time_start":"2025-10-24 18:00:00","gmt_time_end":"2025-10-24 19:00:00","gmt_time_end_last":"2025-10-24 19:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Coda, Room 114","extras":[],"hg_media":{"678418":{"id":"678418","type":"image","title":"Andreas-Stathopoulos.jpg","body":null,"created":"1761148693","gmt_created":"2025-10-22 15:58:13","changed":"1761148693","gmt_changed":"2025-10-22 15:58:13","alt":"CSE Andreas Stathopoulos","file":{"fid":"262441","name":"Andreas-Stathopoulos.jpg","image_path":"\/sites\/default\/files\/2025\/10\/22\/Andreas-Stathopoulos.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2025\/10\/22\/Andreas-Stathopoulos.jpg","mime":"image\/jpeg","size":39914,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2025\/10\/22\/Andreas-Stathopoulos.jpg?itok=cMVCVjrn"}}},"media_ids":["678418"],"groups":[{"id":"47223","name":"College of Computing"},{"id":"50877","name":"School of Computational Science and Engineering"}],"categories":[],"keywords":[{"id":"166983","name":"School of Computational Science and Engineering"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78761","name":"Faculty\/Staff"},{"id":"177814","name":"Postdoc"},{"id":"78771","name":"Public"},{"id":"174045","name":"Graduate students"},{"id":"78751","name":"Undergraduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EEdmond Chow\u0026nbsp;(echow@cc.gatech.edu)\u003C\/p\u003E","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}