sdsl-lite
RoaringBitmap
sdsl-lite | RoaringBitmap | |
---|---|---|
5 | 24 | |
2,174 | 3,390 | |
- | 0.9% | |
0.0 | 8.5 | |
11 months ago | 16 days ago | |
C++ | Java | |
GNU General Public License v3.0 or later | Apache License 2.0 |
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sdsl-lite
- SDSL – Succinct Data Structure Library
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Ask HN: What are some 'cool' but obscure data structures you know about?
Succinct Data Structures [0] [1]. It encompass many different underlying data structure types but the overarching idea is that you want small data size while still keeping "big O" run time.
In other words, data structures that effectively reach a 'practical' entropy lower bound while still keeping asymptotic run time.
[0] https://en.wikipedia.org/wiki/Succinct_data_structure
[1] https://github.com/simongog/sdsl-lite
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SDSL-RS: A Rust interface for the C++ Succinct Data Structure Library.
The book mentioned in another comment is probably the best way to go. But FYI, documentation for some data structures include references. An SDSL-lite example can be found here. And its equivalent in SDSL-RS can be found here.
RoaringBitmap
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Iterating over Bit Sets Quickly
I was recently reading about Roaring https://roaringbitmap.org/ which is a highly optimized compressed bitset implementation. I reccomend reading about it if you are interested in this sort of thing. The talk at https://roaringbitmap.org/talks/ is especially good.
- Roaring Bitmaps
- Roaring bitmaps are compressed bitmaps, can be 100x faster
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What feature would you like to remove in C++26?
However, I would love compressed (not just packed) bitsets too, which is something different to me. I would make it another class with a similar interface, based on something like roaring. It doesn't need to be in the standard, but it would be nice if the API was a such that one could easily swap implementations.
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Jaccard Index
As an aside if you find yourself having to compute them on the fly, know that the Roaring Bitmaps libraries is the way to go [1]. The bitmaps are compressed, and can be streamed directly into SIMD computations (batching XORs and popcnts 256 bits wide!). The Jaccard index is just intersection_len / union_len [2] away
[1] https://roaringbitmap.org/
[2] https://roaringbitmap.readthedocs.io/en/latest/#roaringbitma...
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Looking for fast, space-efficient key-lookup
Use a two stage approach, with a bloom/cuckoo filter stored as a https://roaringbitmap.org/ in memory. Then a secondary key/value store on disk (bolt or anything else).
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BitSet Vs BigInteger
As an aside, if you're dealing with large bit sets, you might also want to evaluate Roaring Bitmaps.
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Negative Incentives in Academic Research
Sidetracking a bit the conversation. What a coincidence that the author (Lemire) is also represented on Today's #1 "Ask HN: What are some cool but obscure data structures you know about?" as he is the main contributor of RoaringBitmap https://github.com/RoaringBitmap/RoaringBitmap and one of the main authors of the data structure.
- Ask HN: What are some 'cool' but obscure data structures you know about?
- Roaring bitmaps: A better compressed bitset
What are some alternatives?
plurid-data-structures-typescript - Utility Data Structures Implemented in TypeScript
HyperMinHash-java - Union, intersection, and set cardinality in loglog space
sdsl-lite - Succinct Data Structure Library 3.0
lucene - Apache Lucene open-source search software
minisketch - Minisketch: an optimized library for BCH-based set reconciliation
CQEngine - Ultra-fast SQL-like queries on Java collections
dictomaton - Finite state dictionaries in Java
Primes - Prime Number Projects in C#/C++/Python
gring - Golang circular linked list with array backend
Feign - Feign makes writing java http clients easier
pyroscope - Continuous Profiling Platform. Debug performance issues down to a single line of code [Moved to: https://github.com/grafana/pyroscope]
maven-compiler-plugin - Apache Maven Compiler Plugin