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Related papers: Bit-Optimal Lempel-Ziv compression

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We introduce height-bounded LZ encodings (LZHB), a new family of compressed representations that are variants of Lempel-Ziv parsings with a focus on bounding the worst-case access time to arbitrary positions in the text directly via the…

Data Structures and Algorithms · Computer Science 2024-04-26 Hideo Bannai , Mitsuru Funakoshi , Diptarama Hendrian , Myuji Matsuda , Simon J. Puglisi

The compression-complexity trade-off of lossy compression algorithms that are based on a random codebook or a random database is examined. Motivated, in part, by recent results of Gupta-Verd\'{u}-Weissman (GVW) and their underlying…

Information Theory · Computer Science 2009-04-23 Chris Gioran , Ioannis Kontoyiannis

Relative Lempel-Ziv (RLZ) parsing is a dictionary compression method in which a string $S$ is compressed relative to a second string $R$ (called the reference) by parsing $S$ into a sequence of substrings that occur in $R$. RLZ is…

Data Structures and Algorithms · Computer Science 2022-08-25 Philip Bille , Inge Li Gørtz , Simon J. Puglisi , Simon R. Tarnow

The Lempel--Ziv 78 (LZ78) factorization is a well-studied technique for data compression. It and its derivatives are used in compression formats such as "compress" or "gif". Although most research focuses on the factorization of plain data,…

Data Structures and Algorithms · Computer Science 2025-12-22 Hiroki Shibata , Dominik Köppl

Today there are many universal compression algorithms, but in most cases is for specific data better using specific algorithm - JPEG for images, MPEG for movies, etc. For textual documents there are special methods based on PPM algorithm or…

Information Theory · Computer Science 2008-12-18 Jan Platos , Jiri Dvorsky

In today's data-centric world, fast and effective compression of data is paramount. To measure success towards the second goal, Kempa and Prezza [STOC2018] introduce the string attractor, a combinatorial object unifying dictionary-based…

Data Structures and Algorithms · Computer Science 2024-07-23 Philip Whittington

Lempel-Ziv-Double (LZD) is a variation of the LZ78 compression scheme that achieves better compression on repetitive datasets. Nevertheless, prior research has identified computational inefficiencies and a weakness in its compressibility…

Data Structures and Algorithms · Computer Science 2025-05-05 Linus Götz , Dominik Köppl

Compression techniques that support fast random access are a core component of any information system. Current state-of-the-art methods group documents into fixed-sized blocks and compress each block with a general-purpose adaptive…

Data Structures and Algorithms · Computer Science 2015-03-19 Christopher Hoobin , Simon J. Puglisi , Justin Zobel

Lempel-Ziv (LZ77) factorization is a fundamental problem in string processing: Greedily partition a given string $T$ from left to right into blocks (called phrases) so that each phrase is either the leftmost occurrence of a letter or the…

Data Structures and Algorithms · Computer Science 2025-06-19 Dominik Kempa , Tomasz Kociumaka

Simple and fast decoding is one of the main advantages of LZ77-type text encoding used in many popular file compressors such as gzip and 7zip. With the recent introduction of external memory algorithms for Lempel-Ziv factorization there is…

Data Structures and Algorithms · Computer Science 2020-12-11 Djamal Belazzougui , Juha Kärkkäinen , Dominik Kempa , Simon J. Puglisi

Relative Lempel-Ziv (RLZ) is a popular algorithm for compressing databases of genomes from individuals of the same species when fast random access is desired. With Kuruppu et al.'s (SPIRE 2010) original implementation, a reference genome is…

Data Structures and Algorithms · Computer Science 2016-05-17 Anthony J. Cox , Andrea Farruggia , Travis Gagie , Simon J. Puglisi , Jouni Sirén

The problem of determining the best achievable performance of arbitrary lossless compression algorithms is examined, when correlated side information is available at both the encoder and decoder. For arbitrary source-side information pairs,…

Information Theory · Computer Science 2020-07-15 Lampros Gavalakis , Ioannis Kontoyiannis

Shannon's entropy is a clear lower bound for statistical compression. The situation is not so well understood for dictionary-based compression. A plausible lower bound is $b$, the least number of phrases of a general bidirectional parse of…

Data Structures and Algorithms · Computer Science 2019-10-29 Gonzalo Navarro , Carlos Ochoa , Nicola Prezza

Domains like bioinformatics, version control systems, collaborative editing systems (wiki), and others, are producing huge data collections that are very repetitive. That is, there are few differences between the elements of the collection.…

Data Structures and Algorithms · Computer Science 2011-12-21 Sebastian Kreft , Gonzalo Navarro

Lempel-Ziv is an easy-to-compute member of a wide family of so-called macro schemes; it restricts pointers to go in one direction only. Optimal bidirectional macro schemes are NP-complete to find, but they may provide much better…

Data Structures and Algorithms · Computer Science 2020-03-06 Luís M. S. Russo , Ana D. Correia , Gonzalo Navarro , Alexandre P. Francisco

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

We study the complexity of constructing an optimal parsing $\varphi$ of a string ${\bf s} = s_1 \dots s_n$ under the constraint that given a position $p$ in the original text, and the LZ76-like (Lempel Ziv 76) encoding of $T$ based on…

Data Structures and Algorithms · Computer Science 2024-03-26 Ferdinando Cicalese , Francesca Ugazio

We introduce the first self-index based on the Lempel-Ziv 1977 compression format (LZ77). It is particularly competitive for highly repetitive text collections such as sequence databases of genomes of related species, software repositories,…

Data Structures and Algorithms · Computer Science 2011-01-24 Sebastian Kreft , Gonzalo Navarro

We study the approximate string matching and regular expression matching problem for the case when the text to be searched is compressed with the Ziv-Lempel adaptive dictionary compression schemes. We present a time-space trade-off that…

Data Structures and Algorithms · Computer Science 2007-05-23 Philip Bille , Rolf Fagerberg , Inge Li Goertz

We consider lossless compression based on statistical data modeling followed by prediction-based encoding, where an accurate statistical model for the input data leads to substantial improvements in compression. We propose DZip, a…

Machine Learning · Computer Science 2020-09-21 Mohit Goyal , Kedar Tatwawadi , Shubham Chandak , Idoia Ochoa