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Intuitively, if two strings $S_1$ and $S_2$ are sufficiently similar and we already have an FM-index for $S_1$ then, by storing a little extra information, we should be able to reuse parts of that index in an FM-index for $S_2$. We…

Data Structures and Algorithms · Computer Science 2014-05-12 Djamal Belazzougui , Travis Gagie , Simon Gog , Giovanni Manzini , Jouni Sirén

We introduce a new family of compressed data structures to efficiently store and query large string dictionaries in main memory. Our main technique is a combination of hierarchical Front-coding with ideas from longest-common-prefix…

Data Structures and Algorithms · Computer Science 2019-11-20 Nieves R. Brisaboa , Ana Cerdeira-Pena , Guillermo de Bernardo , Gonzalo Navarro

Order-preserving pattern matching was introduced recently but it has already attracted much attention. Given a reference sequence and a pattern, we want to locate all substrings of the reference sequence whose elements have the same…

Data Structures and Algorithms · Computer Science 2018-12-11 Gianni Decaroli , Travis Gagie , Giovanni Manzini

We present a novel compressed dynamic self-index for highly repetitive text collections. Signature encoding is a compressed dynamic self-index for highly repetitive texts and has a large disadvantage that the pattern search for short…

Data Structures and Algorithms · Computer Science 2018-04-25 Takaaki Nishimoto , Yoshimasa Takabatake , Yasuo Tabei

Factorization machine (FM) variants are widely used in recommendation systems that operate under strict throughput and latency requirements, such as online advertising systems. FMs are known both due to their ability to model pairwise…

Information Retrieval · Computer Science 2024-08-05 Alex Shtoff , Michael Viderman , Naama Haramaty-Krasne , Oren Somekh , Ariel Raviv , Tularam Ban

Given a text, a query $\mathsf{rank}(q, c)$ counts the number of occurrences of character $c$ among the first $q$ characters of the text. Space-efficient methods to answer these rank queries form an important building block in many succinct…

Data Structures and Algorithms · Computer Science 2026-04-02 R. Groot Koerkamp

Finding desired information from large data set is a difficult problem. Information retrieval is concerned with the structure, analysis, organization, storage, searching, and retrieval of information. Index is the main constituent of an IR…

Information Retrieval · Computer Science 2012-09-26 Md. Abdullah al Mamun , Md. Hanif , Md. Rakib Uddin , Tanvir Ahmed , Md. Mofizul Islam

FM-index is an efficient data structure for string search and is widely used in next-generation sequencing (NGS) applications such as sequence alignment and de novo assembly. Recently, FM-indexing is even performed down to the read level,…

Hardware Architecture · Computer Science 2021-02-08 Nae-Chyun Chen , Yu-Cheng Li , Yi-Chang Lu

Bit vectors with support for fast rank and select are a fundamental building block for compressed data structures. We close a gap between theory and practice by analyzing an important part of the design space and experimentally evaluating a…

Data Structures and Algorithms · Computer Science 2025-09-23 Florian Kurpicz , Niccolò Rigi-Luperti , Peter Sanders

Previous authors have shown how to build FM-indexes efficiently in external memory, but querying them efficiently remains an open problem. Searching na\"{i}vely for a pattern $P$ requires (\Theta (|P|)) random access. In this paper we show…

Data Structures and Algorithms · Computer Science 2012-05-08 Travis Gagie

The problem of proximity full-text search is considered. If a search query contains high-frequently occurring words, then multi-component key indexes deliver an improvement in the search speed compared with ordinary inverted indexes. It was…

Information Retrieval · Computer Science 2021-08-03 Alexander B. Veretennikov

The suffix array is a classic full-text index, combining effectiveness with simplicity. We discuss three approaches aiming to improve its efficiency even more: changes to the navigation, data layout and adding extra data. In short, we show…

Data Structures and Algorithms · Computer Science 2016-07-28 Tomasz Kowalski , Szymon Grabowski , Kimmo Fredriksson , Marcin Raniszewski

The article describes a new data structure called neuro-index. It is an alternative to well-known file indexes. The neuro-index is fundamentally different because it stores weight coefficients in neural network. It is not a reference type…

Information Retrieval · Computer Science 2015-09-08 Valerii Garnaga

The Suffix Array is a classic text index enabling on-line pattern matching queries via simple binary search. The main drawback of the Suffix Array is that it takes linear space in the text's length, even if the text itself is extremely…

Data Structures and Algorithms · Computer Science 2025-03-19 Davide Cenzato , Lore Depuydt , Travis Gagie , Sung-Hwan Kim , Giovanni Manzini , Francisco Olivares , Nicola Prezza

Many large-scale Web applications that require ranked top-k retrieval such as Web search and online advertising are implemented using inverted indices. An inverted index represents a sparse term-document matrix, where non-zero elements…

Information Retrieval · Computer Science 2015-03-19 George Beskales , Marcus Fontoura , Maxim Gurevich , Sergei Vassilvitskii , Vanja Josifovski

This work addresses the problem of billion-scale nearest neighbor search. The state-of-the-art retrieval systems for billion-scale databases are currently based on the inverted multi-index, the recently proposed generalization of the…

Computer Vision and Pattern Recognition · Computer Science 2018-07-24 Dmitry Baranchuk , Artem Babenko , Yury Malkov

We present a distributed full-text index for big data applications in a distributed environment. Our index can answer different types of pattern matching queries (existential, counting and enumeration). We perform experiments on inputs up…

Data Structures and Algorithms · Computer Science 2016-12-07 Johannes Fischer , Florian Kurpicz , Peter Sanders

Ranking bit patterns -- finding the index of a given pattern in an ordered sequence -- is a major bottleneck scaling up numerical quantum many-body calculations, as fermionic and hard-core bosonic states translate naturally to bit patterns.…

Strongly Correlated Electrons · Physics 2022-12-06 Markus Wallerberger , Karsten Held

Dual-encoder-based dense retrieval models have become the standard in IR. They employ large Transformer-based language models, which are notoriously inefficient in terms of resources and latency. We propose Fast-Forward indexes -- vector…

Information Retrieval · Computer Science 2023-11-03 Jurek Leonhardt , Henrik Müller , Koustav Rudra , Megha Khosla , Abhijit Anand , Avishek Anand

Structured distributions, i.e. distributions over combinatorial spaces, are commonly used to learn latent probabilistic representations from observed data. However, scaling these models is bottlenecked by the high computational and memory…

Computation and Language · Computer Science 2022-01-11 Justin T. Chiu , Yuntian Deng , Alexander M. Rush