4bde8a0adb
* Made shuffle and partial_shuffle faster * Use criterion benchmarks for shuffle * Added a note about RNG word size * Tidied comments * Added a debug_assert * Added a comment re possible further optimization * Added and updated copyright notices * Revert cfg mistake * Reverted change to mod.rs * Removed ChaCha20 benches from shuffle * moved debug_assert out of a const fn
112 lines
3.2 KiB
Rust
112 lines
3.2 KiB
Rust
// Copyright 2018-2023 Developers of the Rand project.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use criterion::{black_box, criterion_group, criterion_main, Criterion};
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use rand::prelude::*;
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use rand::SeedableRng;
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criterion_group!(
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name = benches;
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config = Criterion::default();
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targets = bench
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);
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criterion_main!(benches);
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pub fn bench(c: &mut Criterion) {
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bench_rng::<rand_chacha::ChaCha20Rng>(c, "ChaCha20");
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bench_rng::<rand_pcg::Pcg32>(c, "Pcg32");
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bench_rng::<rand_pcg::Pcg64>(c, "Pcg64");
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}
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fn bench_rng<Rng: RngCore + SeedableRng>(c: &mut Criterion, rng_name: &'static str) {
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for length in [1, 2, 3, 10, 100, 1000].map(|x| black_box(x)) {
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c.bench_function(
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format!("choose_size-hinted_from_{length}_{rng_name}").as_str(),
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|b| {
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let mut rng = Rng::seed_from_u64(123);
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b.iter(|| choose_size_hinted(length, &mut rng))
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},
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);
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c.bench_function(
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format!("choose_stable_from_{length}_{rng_name}").as_str(),
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|b| {
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let mut rng = Rng::seed_from_u64(123);
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b.iter(|| choose_stable(length, &mut rng))
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},
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);
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c.bench_function(
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format!("choose_unhinted_from_{length}_{rng_name}").as_str(),
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|b| {
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let mut rng = Rng::seed_from_u64(123);
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b.iter(|| choose_unhinted(length, &mut rng))
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},
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);
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c.bench_function(
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format!("choose_windowed_from_{length}_{rng_name}").as_str(),
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|b| {
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let mut rng = Rng::seed_from_u64(123);
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b.iter(|| choose_windowed(length, 7, &mut rng))
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},
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);
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}
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}
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fn choose_size_hinted<R: Rng>(max: usize, rng: &mut R) -> Option<usize> {
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let iterator = 0..max;
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iterator.choose(rng)
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}
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fn choose_stable<R: Rng>(max: usize, rng: &mut R) -> Option<usize> {
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let iterator = 0..max;
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iterator.choose_stable(rng)
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}
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fn choose_unhinted<R: Rng>(max: usize, rng: &mut R) -> Option<usize> {
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let iterator = UnhintedIterator { iter: (0..max) };
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iterator.choose(rng)
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}
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fn choose_windowed<R: Rng>(max: usize, window_size: usize, rng: &mut R) -> Option<usize> {
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let iterator = WindowHintedIterator {
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iter: (0..max),
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window_size,
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};
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iterator.choose(rng)
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}
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#[derive(Clone)]
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struct UnhintedIterator<I: Iterator + Clone> {
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iter: I,
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}
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impl<I: Iterator + Clone> Iterator for UnhintedIterator<I> {
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type Item = I::Item;
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fn next(&mut self) -> Option<Self::Item> {
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self.iter.next()
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}
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}
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#[derive(Clone)]
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struct WindowHintedIterator<I: ExactSizeIterator + Iterator + Clone> {
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iter: I,
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window_size: usize,
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}
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impl<I: ExactSizeIterator + Iterator + Clone> Iterator for WindowHintedIterator<I> {
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type Item = I::Item;
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fn next(&mut self) -> Option<Self::Item> {
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self.iter.next()
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}
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fn size_hint(&self) -> (usize, Option<usize>) {
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(core::cmp::min(self.iter.len(), self.window_size), None)
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}
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}
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