2 code implementations • 5 Feb 2019 • Daniel Lemire, Owen Kaser, Nathan Kurz
Currently, the remainder of the division by a constant is computed from the quotient by a multiplication and a subtraction.
Mathematical Software Performance
15 code implementations • 22 Sep 2017 • Daniel Lemire, Owen Kaser, Nathan Kurz, Luca Deri, Chris O'Hara, François Saint-Jacques, Gregory Ssi-Yan-Kai
Compressed bitmap indexes are used in systems such as Git or Oracle to accelerate queries.
Databases
13 code implementations • 21 Mar 2016 • Daniel Lemire, Gregory Ssi-Yan-Kai, Owen Kaser
To better handle these cases, we build a new Roaring hybrid that combines uncompressed bitmaps, packed arrays and RLE compressed segments.
Databases
2 code implementations • 11 Mar 2015 • Daniel Lemire, Owen Kaser
Intel and AMD support the Carry-less Multiplication (CLMUL) instruction set in their x64 processors.
Data Structures and Algorithms Performance
14 code implementations • 26 Feb 2014 • Samy Chambi, Daniel Lemire, Owen Kaser, Robert Godin
On synthetic and real data, we find that Roaring bitmaps (1) often compress significantly better (e. g., 2 times) and (2) are faster than the compressed alternatives (up to 900 times faster for intersections).
Databases
4 code implementations • 18 Feb 2014 • Owen Kaser, Daniel Lemire
Compressed bitmap indexes are used to speed up simple aggregate queries in databases.
Databases Data Structures and Algorithms
3 code implementations • 9 Jul 2012 • Daniel Lemire, Owen Kaser, Eduardo Gutarra
For minimizing the number of runs in a run-length encoding compression scheme, the best approaches to row-ordering are derived from traveling salesman heuristics, although there is a significant trade-off between running time and compression.
Databases H.4.0
4 code implementations • 22 Feb 2012 • Owen Kaser, Daniel Lemire
Our tests include hash functions designed for processors with the Carry-Less Multiplication (CLMUL) instruction set.
Databases Data Structures and Algorithms
2 code implementations • 7 Sep 2009 • Daniel Lemire, Owen Kaser
Column-oriented indexes-such as projection or bitmap indexes-are compressed by run-length encoding to reduce storage and increase speed.
Databases
6 code implementations • 23 Jan 2009 • Daniel Lemire, Owen Kaser, Kamel Aouiche
Bitmap indexes must be compressed to reduce input/output costs and minimize CPU usage.
Databases
no code implementations • 13 Jul 2007 • Owen Kaser, Daniel Lemire
We investigate the case of the Project Gutenberg corpus, where most documents are in ASCII format with preambles and epilogues that are often copied and pasted or manually typed.
2 code implementations • 31 May 2007 • Daniel Lemire, Owen Kaser
We prove that recursive hash families cannot be more than pairwise independent.
