Crate out

Provides fast min and max functionality for collections.

let mut v = [-5, 4, 1, -3, 2];
let max = out::slice::max(&mut v, 3);
assert_eq!(max, [1, 2, 4]);

This library can provide significant performance increase compared to sorting or converting to a heap when n is small compared to the length of the slice or iterator.

Benchmarks

n = 100, len = 1_000_000:

openSUSE Tumbleweed, i7-5820K @ 3.30GHz, and 16GiB RAM:

test iter::max                 ... bench:     918,253 ns/iter (+/- 99,863)
test iter::max_unstable        ... bench:     916,908 ns/iter (+/- 58,050)
test slice::max                ... bench:     698,643 ns/iter (+/- 46,373)
test slice::max_by_cached_key  ... bench:   1,516,099 ns/iter (+/- 37,853)
test slice::max_unstable       ... bench:     655,286 ns/iter (+/- 25,017)
test std::binary_heap          ... bench:   6,592,801 ns/iter (+/- 780,590)
test std::sort                 ... bench:  63,192,028 ns/iter (+/- 2,338,506)
test std::sort_by_cached_key   ... bench:  66,058,834 ns/iter (+/- 5,447,387)
test std::sort_unstable        ... bench:  30,953,024 ns/iter (+/- 1,141,696)

Windows 10 (msvc), i7-5820K @ 3.30GHz, and 16GiB RAM:

test iter::max                 ... bench:   2,650,615 ns/iter (+/- 1,427,458)
test iter::max_unstable        ... bench:   2,604,860 ns/iter (+/- 1,001,639)
test slice::max                ... bench:   2,353,487 ns/iter (+/- 1,140,791)
test slice::max_by_cached_key  ... bench:   3,317,930 ns/iter (+/- 1,115,283)
test slice::max_unstable       ... bench:   2,221,975 ns/iter (+/- 1,232,170)
test std::binary_heap          ... bench:   8,666,095 ns/iter (+/- 3,790,987)
test std::sort                 ... bench:  73,953,630 ns/iter (+/- 23,036,689)
test std::sort_by_cached_key   ... bench:  79,681,540 ns/iter (+/- 24,554,555)
test std::sort_unstable        ... bench:  35,327,180 ns/iter (+/- 8,306,700)

Modules

iter	Functions for use with iterators.
slice	Functions for use with slices.