Hopscotch map
C++ implementation of a fast hash map and hash set using hopscotch hashing (by Tessil)
stx-btree
OBSOLETE, contained in https://github.com/tlx/tlx - STX B+ Tree C++ Template Classes - (by bingmann)
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Hopscotch map | stx-btree | |
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3 | 1 | |
698 | 208 | |
- | - | |
3.7 | 0.0 | |
7 months ago | about 1 year ago | |
C++ | HTML | |
MIT License | GNU General Public License v3.0 only |
The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
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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.
Hopscotch map
Posts with mentions or reviews of Hopscotch map.
We have used some of these posts to build our list of alternatives
and similar projects. The last one was on 2022-06-30.
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boost::unordered map is a new king of data structures
Unordered hash map shootout CMAP = https://github.com/tylov/STC KMAP = https://github.com/attractivechaos/klib PMAP = https://github.com/greg7mdp/parallel-hashmap FMAP = https://github.com/skarupke/flat_hash_map RMAP = https://github.com/martinus/robin-hood-hashing HMAP = https://github.com/Tessil/hopscotch-map TMAP = https://github.com/Tessil/robin-map UMAP = std::unordered_map Usage: shootout [n-million=40 key-bits=25] Random keys are in range [0, 2^25). Seed = 1656617916: T1: Insert/update random keys: KMAP: time: 1.949, size: 15064129, buckets: 33554432, sum: 165525449561381 CMAP: time: 1.649, size: 15064129, buckets: 22145833, sum: 165525449561381 PMAP: time: 2.434, size: 15064129, buckets: 33554431, sum: 165525449561381 FMAP: time: 2.112, size: 15064129, buckets: 33554432, sum: 165525449561381 RMAP: time: 1.708, size: 15064129, buckets: 33554431, sum: 165525449561381 HMAP: time: 2.054, size: 15064129, buckets: 33554432, sum: 165525449561381 TMAP: time: 1.645, size: 15064129, buckets: 33554432, sum: 165525449561381 UMAP: time: 6.313, size: 15064129, buckets: 31160981, sum: 165525449561381 T2: Insert sequential keys, then remove them in same order: KMAP: time: 1.173, size: 0, buckets: 33554432, erased 20000000 CMAP: time: 1.651, size: 0, buckets: 33218751, erased 20000000 PMAP: time: 3.840, size: 0, buckets: 33554431, erased 20000000 FMAP: time: 1.722, size: 0, buckets: 33554432, erased 20000000 RMAP: time: 2.359, size: 0, buckets: 33554431, erased 20000000 HMAP: time: 0.849, size: 0, buckets: 33554432, erased 20000000 TMAP: time: 0.660, size: 0, buckets: 33554432, erased 20000000 UMAP: time: 2.138, size: 0, buckets: 31160981, erased 20000000 T3: Remove random keys: KMAP: time: 1.973, size: 0, buckets: 33554432, erased 23367671 CMAP: time: 2.020, size: 0, buckets: 33218751, erased 23367671 PMAP: time: 2.940, size: 0, buckets: 33554431, erased 23367671 FMAP: time: 1.147, size: 0, buckets: 33554432, erased 23367671 RMAP: time: 1.941, size: 0, buckets: 33554431, erased 23367671 HMAP: time: 1.135, size: 0, buckets: 33554432, erased 23367671 TMAP: time: 1.064, size: 0, buckets: 33554432, erased 23367671 UMAP: time: 5.632, size: 0, buckets: 31160981, erased 23367671 T4: Iterate random keys: KMAP: time: 0.748, size: 23367671, buckets: 33554432, repeats: 8, sum: 4465059465719680 CMAP: time: 0.627, size: 23367671, buckets: 33218751, repeats: 8, sum: 4465059465719680 PMAP: time: 0.680, size: 23367671, buckets: 33554431, repeats: 8, sum: 4465059465719680 FMAP: time: 0.735, size: 23367671, buckets: 33554432, repeats: 8, sum: 4465059465719680 RMAP: time: 0.464, size: 23367671, buckets: 33554431, repeats: 8, sum: 4465059465719680 HMAP: time: 0.719, size: 23367671, buckets: 33554432, repeats: 8, sum: 4465059465719680 TMAP: time: 0.662, size: 23367671, buckets: 33554432, repeats: 8, sum: 4465059465719680 UMAP: time: 6.168, size: 23367671, buckets: 31160981, repeats: 8, sum: 4465059465719680 T5: Lookup random keys: KMAP: time: 0.943, size: 23367671, buckets: 33554432, lookups: 34235332, found: 29040438 CMAP: time: 0.863, size: 23367671, buckets: 33218751, lookups: 34235332, found: 29040438 PMAP: time: 1.635, size: 23367671, buckets: 33554431, lookups: 34235332, found: 29040438 FMAP: time: 0.969, size: 23367671, buckets: 33554432, lookups: 34235332, found: 29040438 RMAP: time: 1.705, size: 23367671, buckets: 33554431, lookups: 34235332, found: 29040438 HMAP: time: 0.712, size: 23367671, buckets: 33554432, lookups: 34235332, found: 29040438 TMAP: time: 0.584, size: 23367671, buckets: 33554432, lookups: 34235332, found: 29040438 UMAP: time: 1.974, size: 23367671, buckets: 31160981, lookups: 34235332, found: 29040438
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Yes, this is embarrassingly slow .so I solved your problem
the map member used for the lookups is a tsl::hopscotch_map (https://github.com/Tessil/hopscotch-map), which is a proper hash map. so it seems to be the latter, that the API is wrong, but from what I can tell it is only a wrongly named class. i don't see where the API makes guarantees about iteration order, which is where the implementation difference would be noticeable (beyond performance for lookup).
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Any suggestions for resources to optimize for memory allocation/reallocation?
using an open-addressing hash table, such as abseil flat_hash_map or tessil/hopscotch-map
stx-btree
Posts with mentions or reviews of stx-btree.
We have used some of these posts to build our list of alternatives
and similar projects. The last one was on 2023-04-24.
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Introducing B++ Trees, a C++ B+ Tree library
Apart from persistent mode (which is very cool!), what are design differences with abseil btree and tlx-btree (former stx-btree)?
What are some alternatives?
When comparing Hopscotch map and stx-btree you can also consider the following projects:
C++ B-tree - Git mirror of the official (mercurial) repository of cpp-btree
PEGTL - Parsing Expression Grammar Template Library
Inja - A Template Engine for Modern C++
sparsehash-c11 - Experimental C++11 version of sparsehash
Hashmaps - Various open addressing hashmap algorithms in C++
sparsehash - C++ associative containers
Optional Argument in C++ - Named Optional Arguments in C++17
Hopscotch map vs C++ B-tree
stx-btree vs C++ B-tree
Hopscotch map vs PEGTL
stx-btree vs Inja
Hopscotch map vs sparsehash-c11
stx-btree vs Hashmaps
Hopscotch map vs sparsehash
stx-btree vs sparsehash-c11
Hopscotch map vs Optional Argument in C++
stx-btree vs sparsehash
Hopscotch map vs Hashmaps
stx-btree vs Optional Argument in C++