IR-part1

241 a rst aempt biword indexes index every consecuve

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Unformatted text preview: cessing? §༊  Consider a query that is an AND of n terms. §༊  For each of the n terms, get its pos*ngs, then AND them together. Brutus 2 Caesar 1 Calpurnia 4 2 8 16 32 64 128 3 5 8 16 21 34 13 16 Query: Brutus AND Calpurnia AND Caesar 41 Introduc)on to Informa)on Retrieval Sec. 1.3 Query op*miza*on example §༊  Process in order of increasing freq: §༊  start with smallest set, then keep cuDng further. This is why we kept document freq. in dictionary Brutus 2 Caesar 1 Calpurnia 4 2 8 16 32 64 128 3 5 8 16 21 34 13 16 Execute the query as (Calpurnia AND Brutus) AND Caesar. 42 Introduc)on to Informa)on Retrieval Sec. 1.3 More general op*miza*on §༊  e.g., (madding OR crowd) AND (ignoble OR strife) §༊  Get doc. freq.’s for all terms. §༊  Es*mate the size of each OR by the...
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This document was uploaded on 02/14/2014.

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