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A faster algorithm for constructing minimal perfect hash functions

Edward A. Fox, Qi Fan Chen, Lenwood S. Heath
1992 Proceedings of the 15th annual international ACM SIGIR conference on Research and development in information retrieval - SIGIR '92  
Here, a new algorithm is described for quickly finding minimal perfect hash functions whose specification space is very close to the theoretical lower bound, i.e., around 2 bits per key.  ...  Our previous research on one-probe access to large collections of data indexed by alphanumeric keys has produced the first practical minimal perfect hash functions for this problem.  ...  Algorithm 2 0 2.4 '2.6 2.8 3.0 3.2 3.4 BiwKP.y 6 272 This paper has discussed a new fast algorithm for finding minimal perfect hash functions.  ... 
doi:10.1145/133160.133209 dblp:conf/sigir/FoxCH92 fatcat:vysmvejoxvb4vc6jcafoz4hhoy

A Practical Minimal Perfect Hashing Method [chapter]

Fabiano C. Botelho, Yoshiharu Kohayakawa, Nivio Ziviani
2005 Lecture Notes in Computer Science  
We propose a novel algorithm based on random graphs to construct minimal perfect hash functions h. For a set of n keys, our algorithm outputs h in expected time O(n).  ...  This improves the space requirement to 55% of a previous minimal perfect hashing scheme due to Czech, Havas and Majewski.  ...  Pagh [14] proposed a family of randomized algorithms for constructing minimal perfect hash functions.  ... 
doi:10.1007/11427186_42 fatcat:66g3nyhgcvc4ll7si4kmrmdz2a

A Genetic Algorithm for Obtaining Memory Constrained Near-Perfect Hashing [article]

Dan Domnita, Ciprian Oprisa
2020 arXiv   pre-print
The paper results show that near-perfect hashing is faster than binary search, yet uses less memory than perfect hashing, being a good choice for memory-constrained applications where search time is also  ...  The optimal parameter is determined using a genetic algorithm.  ...  This paper will present near-perfect hashing, a method to optimize the number of searches for an open addressing hash table, by employing a genetic algorithm to find a hash function that minimizes this  ... 
arXiv:2007.08311v1 fatcat:5rdrmumjx5g6zjjsqyjan5yeuq

Perfect Hashing for Network Applications

Yi Lu, Balaji Prabhakar, Flavio Bonomi
2006 2006 IEEE International Symposium on Information Theory  
Our construction is several orders faster than existing perfect hashing schemes.  ...  Existing perfect hashing algorithms are not tailored for network applications because they take too long to construct and are hard to implement in hardware.  ...  MINIMAL PERFECT HASHING Section II-A illustrates the architecture and algorithm of the CBF-based perfect hash.  ... 
doi:10.1109/isit.2006.261567 dblp:conf/isit/LuPB06 fatcat:sy5pitinxbcjfbsqwrfshhy4by

Perfect Hashing for Data Management Applications [article]

Fabiano C. Botelho, Rasmus Pagh, Nivio Ziviani
2007 arXiv   pre-print
We demonstrate the scalability of our algorithm by considering a set of over one billion URLs from the World Wide Web of average length 64, for which we construct a minimal perfect hash function on a commodity  ...  Though there has been considerable work on how to construct good perfect hash functions, there is a gap between theory and practice among all previous methods on minimal perfect hashing.  ...  The internal algorithm We now describe the internal algorithm, a simple and spaceoptimal way of constructing a minimal perfect hash function for a set S of n elements.  ... 
arXiv:cs/0702159v1 fatcat:7zbbgpotnneilnpfh34upd5bhe

Fast and Scalable Minimal Perfect Hashing for Massive Key Sets

Antoine Limasset, Guillaume Rizk, Rayan Chikhi, Pierre Peterlongo, Marc Herbstritt
2017 Symposium on Experimental and Efficient Algorithms  
Minimal perfect hash functions provide space-efficient and collision-free hashing on static sets.  ...  It is capable of creating a minimal perfect hash function of 10 10 elements in less than 7 minutes using 8 threads and 5 GB of memory, and the resulting function uses 3.7 bits/element.  ...  We thank the GenOuest BioInformatics Platform that provided the computing resources necessary for benchmarking. We thank Djamal Belazzougui for helpful discussions and pointers.  ... 
doi:10.4230/lipics.sea.2017.25 dblp:conf/wea/LimassetRCP17 fatcat:upmr6pbsgndexcs4rhmlkmmqti

Blooming Trees for Minimal Perfect Hashing

Gianni Antichi, Domenico Ficara, Stefano Giordano, Gregorio Procissi, Fabio Vitucci
2008 IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference  
In particular, a minimal perfect hash function is a function that maps a set of n keys into a set of n integer numbers without collisions.  ...  In literature, there are many schemes to construct a minimal perfect hash function, either based on mathematical properties of polynomials or on graph theory.  ...  CONCLUSION The paper presents a new solution for the construction of a minimal perfect hash function, which is useful in many networking applications.  ... 
doi:10.1109/glocom.2008.ecp.305 dblp:conf/globecom/AntichiFGPV08 fatcat:wmtuwu36lndufcinbc4q4v6waq

Flash memory efficient LTL model checking

S. Edelkamp, D. Sulewski, J. Barnat, L. Brim, P. Šimeček
2011 Science of Computer Programming  
perfect hash function from RAM to flash memory.  ...  For flash memory efficient off-line LTL model checking, which aims at generating a minimal counterexample and scans the entire state space at least once, we analyze the effect of outsourcing a memory-based  ...  Acknowledgements We would like to thank Martin Dietzfelbinger for his help to derive the lower bound on perfect hashing, Peter Kissmann for his rigorous proof reading, and the anonymous reviewers for the  ... 
doi:10.1016/j.scico.2010.03.005 fatcat:5kkssybrs5dibhqgwyhvsv3xfi

Fast and scalable minimal perfect hashing for massive key sets [article]

Antoine Limasset and Guillaume Rizk and Rayan Chikhi and Pierre Peterlongo
2017 arXiv   pre-print
Minimal perfect hash functions provide space-efficient and collision-free hashing on static sets.  ...  It is capable of creating a minimal perfect hash function of 10^10 elements in less than 7 minutes using 8 threads and 5 GB of memory, and the resulting function uses 3.7 bits/element.  ...  We thank the GenOuest BioInformatics Platform that provided the computing resources necessary for benchmarking. We thank Djamal Belazzougui for helpful discussions and pointers.  ... 
arXiv:1702.03154v2 fatcat:cfzd4fyw2jdxhp2ls3rwdnnlsy

Rescore in a Flash: Compact, Cache Efficient Hashing Data Structures for n-Gram Language Models

Grant P. Strimel, Ariya Rastrow, Gautam Tiwari, Adrien Piérard, Jon Webb
2020 Interspeech 2020  
We detail the algorithm and justify our design choices with comparative experiments on a speech recognition task.  ...  We also present variations of Dash-HashLM appropriate for scenarios with different memory and latency constraints.  ...  Perfect Hashing In perfect hashing, a function maps a set S of ns keys into m buckets with no collisions. A Minimal Perfect Hash Function (MPHF) hashes S into ns buckets with no collisions.  ... 
doi:10.21437/interspeech.2020-1939 dblp:conf/interspeech/StrimelRTPW20 fatcat:djxokflyo5dtdb2v6m7xloqgr4

Perfect Spatial Hashing for Point-cloud-to-mesh Registration

Daniel Mejia-Parra, Juan Lalinde-Pulido, Jairo R. Sánchez, Oscar Ruiz-Salguero, Jorge Posada
2019 Spanish Computer Graphics Conference  
To overcome this problem, this article presents the implementation of a Perfect Spatial Hashing for point-cloud-to-mesh registration.  ...  The complexity of the registration algorithm using Perfect Spatial Hashing is O(NYxn) (NY : point cloud size, n: number of max.  ...  Therefore, the computational cost for the Perfect Spatial Hash construction is O(N T + (N 3 H ) 2 ) Figure 6 : 6 Algorithm scheme for the construction of the Perfect Spatial Hash (H, h) Figure 7 :  ... 
doi:10.2312/ceig.20191202 dblp:conf/ceig/Mejia-ParraLSRP19 fatcat:4qu64w7ge5h6fecxunzjcv2o5q

Practical perfect hashing in nearly optimal space

Fabiano C. Botelho, Rasmus Pagh, Nivio Ziviani
2013 Information Systems  
A minimal perfect hash function for some set S ⊆ U is a perfect hash function with a range of minimum size, i.e., m = |S |.  ...  By taking into account the memory hierarchy we can construct (minimal) perfect hash functions for over a billion keys in 46 minutes using a commodity PC.  ...  A minimal perfect hash function (MPHF), for some set S ⊆ U, is a perfect hash function with a range of minimum size, i.e., m = |S |.  ... 
doi:10.1016/j.is.2012.06.002 fatcat:hn6si7ptnrgylfgvkgxlpsebai

PTHash: Revisiting FCH Minimal Perfect Hashing [article]

Giulio Ermanno Pibiri, Roberto Trani
2021 arXiv   pre-print
Given a set S of n distinct keys, a function f that bijectively maps the keys of S into the range {0,...,n-1} is called a minimal perfect hash function for S.  ...  Algorithms that find such functions when n is large and retain constant evaluation time are of practical interest; for instance, search engines and databases typically use minimal perfect hash functions  ...  It would be also interesting to generalize the algorithm to build other types of functions, such as perfect (non-minimal), and -perfect hash functions.  ... 
arXiv:2104.10402v1 fatcat:s5dvbkhkezf75lo3jn6evruz64

An optimal algorithm for generating minimal perfect hash functions

Zbigniew J. Czech, George Havas, Bohdan S. Majewski
1992 Information Processing Letters  
A new algorithm for generating order preserving minimal perfect hash functions is presented. The algorithm is probabilistic, involving generation of random graphs.  ...  It uses expected linear time and requires a linear number words to represent the hash function, and thus is optimal up to constant factors. It runs very fast in practice.  ...  Various algorithms with different time complexities have been presented for constructing perfect or minimal perfect hash functions, including [3, 4, 5, 6, 7, 8, 17, 10, 19, 20, 22, 30] .  ... 
doi:10.1016/0020-0190(92)90220-p fatcat:te6smawya5a57lzeelijopovtm

Fast Scalable Construction of (Minimal Perfect Hash) Functions [article]

Marco Genuzio, Giuseppe Ottaviano, Sebastiano Vigna
2016 arXiv   pre-print
Recent advances in random linear systems on finite fields have paved the way for the construction of constant-time data structures representing static functions and minimal perfect hash functions using  ...  Our implementation of these techniques yields a minimal perfect hash function data structure occupying 2.24 bits per element, compared to 2.68 for MWHC-based ones, and a static function data structure  ...  Conclusions We have discussed new practical data structures for static functions and minimal perfect hash functions.  ... 
arXiv:1603.04330v2 fatcat:ef3exwqa6ffq3davamqv6yzaii
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