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Related papers: Self-Index Based on LZ77

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As large language models (LLMs) continue to be deployed and utilized across domains, the volume of LLM-generated data is growing rapidly. This trend highlights the increasing importance of effective and lossless compression for such data in…

Machine Learning · Computer Science 2025-05-13 Yu Mao , Holger Pirk , Chun Jason Xue

We describe a data structure that stores a string $S$ in space similar to that of its Lempel-Ziv encoding and efficiently supports access, rank and select queries. These queries are fundamental for implementing succinct and compressed data…

Data Structures and Algorithms · Computer Science 2014-12-03 Djamal Belazzougui , Travis Gagie , Paweł Gawrychowski , Juha Kärkkäinen , Alberto Ordóñez , Simon J. Puglisi , Yasuo Tabei

The FM-index is a celebrated compressed data structure for full-text pattern searching. After the first wave of interest in its theoretical developments, we can observe a surge of interest in practical FM-index variants in the last few…

Data Structures and Algorithms · Computer Science 2015-10-27 Szymon Grabowski , Marcin Raniszewski , Sebastian Deorowicz

We describe how, given a text $T [1..n]$ and a positive constant $\epsilon$, we can build a simple $O (z \log n)$-space index, where $z$ is the number of phrases in the LZ77 parse of $T$, such that later, given a pattern $P [1..m]$, in $O…

Data Structures and Algorithms · Computer Science 2022-12-06 Nick Fagan , Jorge Hermo González , Travis Gagie

LZ77-based compression schemes compress the input text by replacing factors in the text with an encoded reference to a previous occurrence formed by the couple (length, offset). For a given factor, the smallest is the offset, the smallest…

Data Structures and Algorithms · Computer Science 2012-11-22 Maxime Crochemore , Alessio Langiu , Filippo Mignosi

This article introduces a new DNA sequence compression algorithm which is based on LUT and LZ77 algorithm. Combined a LUT-based pre-coding routine and LZ77 compression routine,this algorithm can approach a compression ratio of 1.9bits…

Information Theory · Computer Science 2007-07-16 Sheng Bao , Shi Chen , Zhiqiang Jing , Ran Ren

Compression refers to encoding data using bits, so that the representation uses as few bits as possible. Compression could be lossless: i.e. encoded data can be recovered exactly from its representation) or lossy where the data is…

Information Theory · Computer Science 2012-10-19 Narayana Santhanam , Dharmendra Modha

Efficient methods for storing and querying are critical for scaling high-order n-gram language models to large corpora. We propose a language model based on compressed suffix trees, a representation that is highly compact and can be easily…

Computation and Language · Computer Science 2016-08-17 Ehsan Shareghi , Matthias Petri , Gholamreza Haffari , Trevor Cohn

The accelerating pace of research on autoregressive generative models has produced thousands of papers, making manual literature surveys and reproduction studies increasingly impractical. We present a fully open-source, reproducible…

Information Retrieval · Computer Science 2025-08-07 Faruk Alpay , Bugra Kilictas , Hamdi Alakkad

The paper proposes an improved error-resilient Lempel-Ziv'77 (LZ'77) algorithm employing an adaptive amount of parity bits for error protection. It is a modified version of error resilient algorithm LZRS'77, proposed recently, which uses a…

Information Theory · Computer Science 2008-04-21 Tomaz Korosec , Saso Tomazic

In this paper, we present the first study of the computational complexity of converting an automata-based text index structure, called the Compact Directed Acyclic Word Graph (CDAWG), of size $e$ for a text $T$ of length $n$ into other text…

Data Structures and Algorithms · Computer Science 2023-08-07 Hiroki Arimura , Shunsuke Inenaga , Yasuaki Kobayashi , Yuto Nakashima , Mizuki Sue

We provide new estimates of an asymptotic upper bound on the entropy of English using the large language model LLaMA-7B as a predictor for the next token given a window of past tokens. This estimate is significantly smaller than currently…

Suffix trees are one of the most versatile data structures in stringology, with many applications in bioinformatics. Their main drawback is their size, which can be tens of times larger than the input sequence. Much effort has been put into…

Data Structures and Algorithms · Computer Science 2017-12-18 Andrea Farruggia , Travis Gagie , Gonzalo Navarro , Simon J. Puglisi , Jouni Sirén

Retrieving documents and prepending them in-context at inference time improves performance of language model (LMs) on a wide range of tasks. However, these documents, often spanning hundreds of words, make inference substantially more…

Computation and Language · Computer Science 2023-10-09 Fangyuan Xu , Weijia Shi , Eunsol Choi

Unlike in statistical compression, where Shannon's entropy is a definitive lower bound, no such clear measure exists for the compressibility of repetitive sequences. Since statistical entropy does not capture repetitiveness, ad-hoc measures…

Data Structures and Algorithms · Computer Science 2021-01-18 Tomasz Kociumaka , Gonzalo Navarro , Nicola Prezza

Pattern matching is the most central task for text indices. Most recent indices leverage compression techniques to make pattern matching feasible for massive but highly-compressible datasets. Within this kind of indices, we propose a new…

Data Structures and Algorithms · Computer Science 2021-05-31 Tooru Akagi , Dominik Köppl , Yuto Nakashima , Shunsuke Inenaga , Hideo Bannai , Masayuki Takeda

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

The fundamental question considered in algorithms on strings is that of indexing, that is, preprocessing a given string for specific queries. By now we have a number of efficient solutions for this problem when the queries ask for an exact…

Data Structures and Algorithms · Computer Science 2023-04-04 Paweł Gawrychowski , Garance Gourdel , Tatiana Starikovskaya , Teresa Anna Steiner

Retrieval-Augmented Generation (RAG) enhances coding tasks by incorporating retrieved code examples into prompts. However, lengthy prompts, often exceeding tens of thousands of tokens, introduce challenges related to limited context windows…

Software Engineering · Computer Science 2026-04-13 Pengfei He , Shaowei Wang , Tse-Hsun Chen

In this paper, a new compression scheme for text is presented. The same is efficient in giving high compression ratios and enables super fast searching within the compressed text. Typical compression ratios of 70-80% and reducing the search…

Information Retrieval · Computer Science 2007-07-16 Udayan Khurana , Anirudh Koul