Letter-oriented reciprocal hashing scheme

Chang, Ching-Rong

doi:10.1016/0020-0255(86)90024-1

Cited by 5 publications

(2 citation statements)

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“…Jaeschke [23] suggests a reciprocal hashing scheme with three parameters that is guaranteed to find a MPHF, but it is only practical when n -< 20. Chang [5] proposes a method with only one parameter, though its value is likely to be very large, and requires a function that assigns a distinct prime to each key. However since he gives no algorithm for that function, the method is only of theoretical interest.…”

Section: Classes Of Functionsmentioning

confidence: 99%

Practical minimal perfect hash functions for large databases

et al. 1992

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Section: Classes Of Functionsmentioning

confidence: 99%

Practical minimal perfect hash functions for large databases

et al. 1992

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“…The first type of approach involves directly searching for a proper function-i.e., using a "search-only" strategy [SPRU78], [JAES81], [CHAN86]. A class of functions is often chosen, and constants are sought such that hashing can take place without collisions.…”

Section: Introductionmentioning

confidence: 99%

A more cost effective algorithm for finding perfect hash functions

Fox

Chen

Heath

et al. 1989

Proceedings of the Seventeenth Annual ACM Conference on Computer Science : Computing Trends in the 1990's Computing Trends in T

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of these contexts there are large static collections of records which must be indexed by keys, usually English words or phrases. Hashing is one method that can provide the desired rapid access, with little overhead in space, but unless the hash function chosen is suitable, there can be a considerable loss in performance due to collisions. Given adequate space, dynamic hashing methods have been developed to deal with this problem in changeable collections [ENBO88]. With static data sets, however, it is possible to build so-called "perfect" hash functions that require minimal space for the hash table, and which entirely avoid the problem of collisions.Electronic mail to: fox@vtopus.cs.vt.eduAs the use of knowledge-based systems increases, there will be a growing need for efficient artificial intelligence systems and methods to access large lexicons. In the COmposite Document Expert/extended/effective Retrieval (CODER) system we have, in order to provide rapid access to data items on CD-ROMs and to terms in a lexicon built from machine readable dictionaries, investigated the construction of perfect hash functions. We have considered algorithms reported earlier in the literature, have made numerous enhancements to them, have developed new algorithms, and here report on some of our results. This paper covers an O(n 3) algorithm that has been applied to building hash functions for a collection of 69806 words on a CD-ROM. Most recently we have developed a much better algorithm and have succeeded in finding a perfect hash function for a set of 130,199 words taken from sources including the Collins English Dictionary.

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The study of letter-oriented hashing schemes

Tang

Louis

1995

Journal of Systems and Software

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Letter-oriented reciprocal hashing scheme

Cited by 5 publications

References 5 publications

Practical minimal perfect hash functions for large databases

Practical minimal perfect hash functions for large databases

A more cost effective algorithm for finding perfect hash functions

The study of letter-oriented hashing schemes

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