PT Unknown
AU Chierichetti, F
Lattanzi, S
Mari, F
Panconesi, A
TI On Placing Skips Optimally in Expectation
BT Web Search and Web Data Mining (WSDM 2008)
PY 2008
BP 15
EP 24
DI 10.1145/1341531.1341537
DE Information Retrieval
AB We study the problem of optimal skip placement in an inverted list. Assuming the query distribution to be known in advance, we formally prove that an optimal skip placement can be computed quite efficiently. Our best algorithm runs in time O(n log n), n being the length of the list. The placement is optimal in the sense that it minimizes the expected time to process a query. Our theoretical results are matched by experiments with a real corpus, showing that substantial savings can be obtained with respect to the tra- ditional skip placement strategy, that of placing consecutive skips, each spanning sqrt(n) many locations.
ER