bit-smasher
RoaringBitmap
| bit-smasher | RoaringBitmap | |
|---|---|---|
| 1 | 24 | |
| 50 | 3,390 | |
| - | 0.9% | |
| 3.6 | 8.5 | |
| almost 2 years ago | 15 days ago | |
| Common Lisp | Java | |
| MIT License | Apache License 2.0 |
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bit-smasher
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Seeking: efficient CL bitsets.
Do you mean bit vectors? Common Lisp has them in the standard and https://github.com/thephoeron/bit-smasher is also useful for handling them.
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?
cl-ssh-keys - Common Lisp system for generating and parsing of OpenSSH keys
HyperMinHash-java - Union, intersection, and set cardinality in loglog space
Primes - Prime Number Projects in C#/C++/Python
lucene - Apache Lucene open-source search software
bit-ops - Tools for writing optimized bit-vector routines
CQEngine - Ultra-fast SQL-like queries on Java collections
cl-intset - A library for non-negative integer sets. It implements sets using bitsets.
Feign - Feign makes writing java http clients easier
maven-compiler-plugin - Apache Maven Compiler Plugin
alexandria - Full text search engine powering Alexandria.org - the open search engine.
Deeplearning4j - Suite of tools for deploying and training deep learning models using the JVM. Highlights include model import for keras, tensorflow, and onnx/pytorch, a modular and tiny c++ library for running math code and a java based math library on top of the core c++ library. Also includes samediff: a pytorch/tensorflow like library for running deep learning using automatic differentiation.