stutter
RoaringBitmap
| stutter | RoaringBitmap | |
|---|---|---|
| 1 | 24 | |
| 73 | 3,388 | |
| - | 0.8% | |
| 1.8 | 8.5 | |
| almost 2 years ago | 11 days ago | |
| C | Java | |
| MIT License | Apache License 2.0 |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
stutter
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Ask HN: What are some 'cool' but obscure data structures you know about?
This. Roughly a year ago I got interested in efficient immutability for my write-from-scratch-in-C Lisp [0] and started to write a HAMT implementation in C [1], along with a (somewhat hacky, you have been warned) benchmarking suite [2].
The docs are only 70% done (in particular the "putting it all together" part is missing) but it has been a really interesting and enlightening journey so far and can only recommend embarking on this path to everyone.
[0]: https://github.com/mkirchner/stutter
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?
ravi-compiler - Parser and compiler for Ravi and Lua
HyperMinHash-java - Union, intersection, and set cardinality in loglog space
Caffeine - A high performance caching library for Java
lucene - Apache Lucene open-source search software
us - An alternative interface to Sia
CQEngine - Ultra-fast SQL-like queries on Java collections
sdsl-lite - Succinct Data Structure Library 2.0
Primes - Prime Number Projects in C#/C++/Python
pyroscope - Continuous Profiling Platform. Debug performance issues down to a single line of code [Moved to: https://github.com/grafana/pyroscope]
Feign - Feign makes writing java http clients easier
FusionCache - FusionCache is an easy to use, fast and robust cache with advanced resiliency features and an optional distributed 2nd level.
maven-compiler-plugin - Apache Maven Compiler Plugin