emhash
Fast and memory efficient c++ flat hash map/set (by ktprime)
unordered
Boost.org unordered module (by boostorg)
| emhash | unordered | |
|---|---|---|
| 2 | 10 | |
| 411 | 53 | |
| - | - | |
| 8.1 | 9.2 | |
| 3 days ago | 4 days ago | |
| C++ | C++ | |
| MIT License | Boost Software License 1.0 |
The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
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.
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.
emhash
Posts with mentions or reviews of emhash.
We have used some of these posts to build our list of alternatives
and similar projects. The last one was on 2022-11-18.
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Inside boost::unordered_flat_map
me author of emhash, I make some optimiazation of swiss table emilib https://github.com/ktprime/emhash/blob/master/thirdparty/emilib/emilib2o.hpp
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Advancing the state of the art for <code>std::unordered_map</code> implementations
O(1) iteration is fine in my flat hash map https://github.com/ktprime/emhash/blob/master/hash_table8.hpp
unordered
Posts with mentions or reviews of unordered.
We have used some of these posts to build our list of alternatives
and similar projects. The last one was on 2023-03-02.
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Effortless Performance Improvements in C++: std::unordered_map
We added two new benchmarks to Boost.Unordered, word_count and word_size, and the second one ends up testing a small hash table (114 elements in 64 bit, even fewer in 32 bit because we use a smaller input file there.)
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Inside boost::unordered_flat_map
Hi, we have seen similar gains with __forceinline in MSVC, looks like this compiler is not particularly aggressive at inlining. Could you please file an issue at Boost.Unordered repo so what we don't forget? Thank you
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Boost 1.81 will have boost::unordered_flat_map...
You can request a feature be added by opening an issue in https://github.com/boostorg/unordered.
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boost::unordered map is a new king of data structures
Here are the results of our uint32.cpp synthetic benchmark under VS2022 Release x64:
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Advancing the state of the art for <code>std::unordered_map</code> implementations
You can run these benchmarks yourself from the Boost develop branch, they are in the Unordered repo. Since Unordered is header-only, there should be need to build Boost but you do need to bootstrap and then run b2 headers to create the symlinks in boost/.
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New Boost.Unordered containers have BIG improvements!
Make sure you checkout the preview.md for instructions on how to build nightly Boost in a way that's non-intrusive to your system and works with CMake.
What are some alternatives?
When comparing emhash and unordered you can also consider the following projects:
robin-map - C++ implementation of a fast hash map and hash set using robin hood hashing
flat_hash_map - A very fast hashtable
unordered_dense - A fast & densely stored hashmap and hashset based on robin-hood backward shift deletion
FetchBoostContent - CMake FetchContent for Boost libraries
hashtable-benchmarks - An Evaluation of Linear Probing Hashtable Algorithms
Hopscotch map - C++ implementation of a fast hash map and hash set using hopscotch hashing
boostdep - A tool to create Boost module dependency reports
parallel-hashmap - A family of header-only, very fast and memory-friendly hashmap and btree containers.
robin-hood-hashing - Fast & memory efficient hashtable based on robin hood hashing for C++11/14/17/20
Klib - A standalone and lightweight C library
emhash vs robin-map
unordered vs flat_hash_map
emhash vs unordered_dense
unordered vs FetchBoostContent
emhash vs hashtable-benchmarks
unordered vs unordered_dense
unordered vs Hopscotch map
unordered vs boostdep
unordered vs robin-map
unordered vs parallel-hashmap
unordered vs robin-hood-hashing
unordered vs Klib