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Support custom key type #69

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merged 5 commits into from
Nov 23, 2024
Merged

Support custom key type #69

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176deb7
Support custom key type
jakoschiko Oct 30, 2024
331ced3
Add unnecessary bounds for Int
jakoschiko Nov 7, 2024
188ced2
Improve doc
jakoschiko Nov 7, 2024
82ec86f
Support custom prime
jakoschiko Nov 7, 2024
f21f6d9
Fix typo
jakoschiko Nov 21, 2024
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4 changes: 2 additions & 2 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -3,12 +3,12 @@ name = "intmap"
version = "2.0.0"
edition = "2021"
rust-version = "1.58"
description = "Specialized HashMap for u64 keys"
description = "Specialized HashMap for integer keys"
authors = ["Jesper Axelsson <[email protected]>"]
readme = "README.md"
license = "MIT"
repository = "https://github.com/JesperAxelsson/rust-intmap"
keywords = ["hashmap", "u64", "intmap"]
keywords = ["hashmap", "int", "intmap"]

[dependencies]
serde = { version = "1.0", optional = true, default-features = false }
Expand Down
6 changes: 3 additions & 3 deletions README.md
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@@ -1,7 +1,7 @@
[![crates.io](https://img.shields.io/crates/v/intmap.svg)](https://crates.io/crates/intmap)

# rust-intmap
Specialized hashmap for `u64` keys
Specialized hashmap for integer keys.

Might be missing some functionality but you can remove, add, get and clear for now.

Expand Down Expand Up @@ -53,12 +53,12 @@ for i in 0..20_000 {
```

# How can it be so much faster?
I use a specialized hash function for `u64` which multiplies the key with the largest prime for `u64`. By keeping the internal cache a power 2 you can avoid the expensive modulus operator as mentioned in [this Stack Overflow post](http://stackoverflow.com/questions/6670715/mod-of-power-2-on-bitwise-operators). The hash function looks like this:
I use a specialized hash function for integers which multiplies the key with the their largest prime. By keeping the internal cache a power 2 you can avoid the expensive modulus operator as mentioned in [this Stack Overflow post](http://stackoverflow.com/questions/6670715/mod-of-power-2-on-bitwise-operators). The hash function looks like this:
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```rust
#[inline]
fn hash_u64(seed: u64) -> u64 {
let a = 11400714819323198549u64;
let a = 18446744073709551611u64;
let val = a.wrapping_mul(seed);
val
}
Expand Down
1 change: 1 addition & 0 deletions integration_tests/Cargo.lock
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4 changes: 4 additions & 0 deletions integration_tests/benchmark/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -16,3 +16,7 @@ rand = "0.8.5"
[[bench]]
name = "basic_bench"
harness = false

[[bench]]
name = "key_comparison"
harness = false
79 changes: 40 additions & 39 deletions integration_tests/benchmark/benches/basic_bench.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -17,13 +17,13 @@ fn main() {
#[bench]
fn u64_insert_built_in(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map = HashMap::with_capacity(data.len());
let mut map: HashMap<u64, u64> = HashMap::with_capacity(data.len());

bencher.bench_local(|| {
map.clear();

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}
});
}
Expand All @@ -33,10 +33,10 @@ fn u64_insert_without_capacity_built_in(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);

bencher.bench_local(|| {
let mut map = HashMap::new();
let mut map: HashMap<u64, u64> = HashMap::new();

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

black_box(&map);
Expand All @@ -46,10 +46,10 @@ fn u64_insert_without_capacity_built_in(bencher: Bencher) {
#[bench]
fn u64_get_built_in(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map: HashMap<&u64, &u64> = HashMap::with_capacity(data.len());
let mut map: HashMap<u64, u64> = HashMap::with_capacity(data.len());

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

bencher.bench_local(|| {
Expand Down Expand Up @@ -87,13 +87,14 @@ impl std::hash::BuildHasher for NoOpHasher {
#[bench]
fn u64_insert_no_op(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map = HashMap::with_capacity_and_hasher(data.len(), NoOpHasher(0));
let mut map: HashMap<u64, u64, NoOpHasher> =
HashMap::with_capacity_and_hasher(data.len(), NoOpHasher(0));

bencher.bench_local(|| {
map.clear();

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}
});
}
Expand All @@ -103,10 +104,10 @@ fn u64_insert_without_capacity_no_op(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);

bencher.bench_local(|| {
let mut map = HashMap::with_hasher(NoOpHasher(0));
let mut map: HashMap<u64, u64, NoOpHasher> = HashMap::with_hasher(NoOpHasher(0));

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

black_box(&map);
Expand All @@ -116,11 +117,11 @@ fn u64_insert_without_capacity_no_op(bencher: Bencher) {
#[bench]
fn u64_get_no_op(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map: HashMap<&u64, &u64, NoOpHasher> =
let mut map: HashMap<u64, u64, NoOpHasher> =
HashMap::with_capacity_and_hasher(data.len(), NoOpHasher(0));

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

bencher.bench_local(|| {
Expand All @@ -135,13 +136,13 @@ fn u64_get_no_op(bencher: Bencher) {
#[bench]
fn u64_insert_brown(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map = BrownMap::with_capacity(data.len());
let mut map: BrownMap<u64, u64> = BrownMap::with_capacity(data.len());

bencher.bench_local(|| {
map.clear();

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}
});
}
Expand All @@ -151,10 +152,10 @@ fn u64_insert_without_capacity_brown(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);

bencher.bench_local(|| {
let mut map = BrownMap::new();
let mut map: BrownMap<u64, u64> = BrownMap::new();

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

black_box(&map);
Expand All @@ -164,10 +165,10 @@ fn u64_insert_without_capacity_brown(bencher: Bencher) {
#[bench]
fn u64_get_brown(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map: BrownMap<&u64, &u64> = BrownMap::with_capacity(data.len());
let mut map: BrownMap<u64, u64> = BrownMap::with_capacity(data.len());

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

bencher.bench_local(|| {
Expand All @@ -182,13 +183,13 @@ fn u64_get_brown(bencher: Bencher) {
#[bench]
fn u64_insert_ahash(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map = AHashMap::with_capacity(data.len());
let mut map: AHashMap<u64, u64> = AHashMap::with_capacity(data.len());

bencher.bench_local(|| {
map.clear();

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}
});
}
Expand All @@ -198,10 +199,10 @@ fn u64_insert_without_capacity_ahash(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);

bencher.bench_local(|| {
let mut map = AHashMap::new();
let mut map: AHashMap<u64, u64> = AHashMap::new();

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

black_box(&map);
Expand All @@ -211,10 +212,10 @@ fn u64_insert_without_capacity_ahash(bencher: Bencher) {
#[bench]
fn u64_get_ahash(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map: AHashMap<&u64, &u64> = AHashMap::with_capacity(data.len());
let mut map: AHashMap<u64, u64> = AHashMap::with_capacity(data.len());

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

bencher.bench_local(|| {
Expand All @@ -229,24 +230,24 @@ fn u64_get_ahash(bencher: Bencher) {
#[bench]
fn u64_insert_indexmap(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map = IndexMap::with_capacity(data.len());
let mut map: IndexMap<u64, u64> = IndexMap::with_capacity(data.len());

bencher.bench_local(|| {
map.clear();

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}
});
}

#[bench]
fn u64_get_indexmap(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map: IndexMap<&u64, &u64> = IndexMap::with_capacity(data.len());
let mut map: IndexMap<u64, u64> = IndexMap::with_capacity(data.len());

for s in data.iter() {
black_box(map.insert(s, s));
black_box(map.insert(*s, *s));
}

bencher.bench_local(|| {
Expand All @@ -261,27 +262,27 @@ fn u64_get_indexmap(bencher: Bencher) {
#[bench]
fn u64_insert_intmap(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map = IntMap::with_capacity(data.len());
let mut map: IntMap<u64, u64> = IntMap::with_capacity(data.len());

bencher.bench_local(|| {
map.clear();

for s in data.iter() {
black_box(map.insert(*s, s));
black_box(map.insert(*s, *s));
}
});
}

#[bench]
fn u64_insert_intmap_checked(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);
let mut map = IntMap::with_capacity(data.len());
let mut map: IntMap<u64, u64> = IntMap::with_capacity(data.len());

bencher.bench_local(|| {
map.clear();

for s in data.iter() {
black_box(map.insert_checked(*s, s));
black_box(map.insert_checked(*s, *s));
}
});
}
Expand All @@ -290,15 +291,15 @@ fn u64_insert_intmap_checked(bencher: Bencher) {
fn u64_insert_intmap_entry(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);

let mut map = IntMap::with_capacity(data.len());
let mut map: IntMap<u64, u64> = IntMap::with_capacity(data.len());

bencher.bench_local(|| {
map.clear();

for s in data.iter() {
black_box(match map.entry(*s) {
Entry::Occupied(_) => panic!("unexpected while insert, i = {}", s),
Entry::Vacant(entry) => entry.insert(s),
Entry::Vacant(entry) => entry.insert(*s),
});
}
});
Expand All @@ -309,10 +310,10 @@ fn u64_insert_without_capacity_intmap(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);

bencher.bench_local(|| {
let mut map = IntMap::new();
let mut map: IntMap<u64, u64> = IntMap::new();

for s in data.iter() {
black_box(map.insert(*s, s));
black_box(map.insert(*s, *s));
}

black_box(&map);
Expand All @@ -322,7 +323,7 @@ fn u64_insert_without_capacity_intmap(bencher: Bencher) {
#[bench]
fn u64_resize_intmap(bencher: Bencher) {
bencher.bench_local(|| {
let mut map: IntMap<u64> = IntMap::new();
let mut map: IntMap<u64, u64> = IntMap::new();
map.reserve(VEC_COUNT);
black_box(&map);
});
Expand All @@ -332,9 +333,9 @@ fn u64_resize_intmap(bencher: Bencher) {
fn u64_get_intmap(bencher: Bencher) {
let data = get_random_range(VEC_COUNT);

let mut map = IntMap::with_capacity(data.len());
let mut map: IntMap<u64, u64> = IntMap::with_capacity(data.len());
for s in data.iter() {
map.insert(*s, s);
map.insert(*s, *s);
}

bencher.bench_local(|| {
Expand Down
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