Upper Bound Approximations for BlockMaxWand

Macdonald, C. and Tonellotto, N. (2017) Upper Bound Approximations for BlockMaxWand. In: The 3rd ACM International Conference on the Theory of Information Retrieval (ICTIR 2017), Amsterdam, The Netherlands, 1-4 Oct 2017, pp. 273-276. ISBN 9781450344906 (doi: 10.1145/3121050.3121094)

Abstract

BlockMaxWand is a recent advance on the Wand dynamic pruning technique, which allows efficient retrieval without any effectiveness degradation to rank K. However, while BMW uses docid-sorted indices, it relies on recording the upper bound of the term weighting model scores for each block of postings in the inverted index. Such a requirement can be disadvantageous in situations such as when an index must be updated. In this work, we examine the appropriateness of upper-bound approximation – which have previously been shown suitable for Wand– in providing efficient retrieval for BMW. Experiments on the ClueWeb12 category B13 corpus using 5000 queries from a real search engine’s query log demonstrate that BMW still provides benefits w.r.t. Wand when approximate upper bounds are used, and that, if approximations on upper bounds are tight, BMW with approximate upper bounds can provide efficiency gains w.r.t.Wand with exact upper bounds, in particular for queries of short to medium length.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Macdonald, Professor Craig
• Authors: Macdonald, C., and Tonellotto, N.
• College/School: College of Science and Engineering > School of Computing Science
• ISBN: 9781450344906
• Copyright Holders: Copyright © 2017 The Authors
• First Published: First published in ICTIR '17 Proceedings of the ACM SIGIR International Conference on Theory of Information Retrieval: 273-276
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher