Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Faster and Better weak generators #59

Closed
wants to merge 1 commit into from
Closed

Faster and Better weak generators #59

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
110 changes: 60 additions & 50 deletions benches/bench.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,64 +3,74 @@
extern crate test;
extern crate rand;

const RAND_BENCH_N: u64 = 100;

mod distributions;

use std::mem::size_of;
use test::{black_box, Bencher};
use rand::{XorShiftRng, StdRng, IsaacRng, Isaac64Rng, Rng};
use rand::{OsRng, weak_rng};

#[bench]
fn rand_xorshift(b: &mut Bencher) {
let mut rng: XorShiftRng = OsRng::new().unwrap().gen();
b.iter(|| {
for _ in 0..RAND_BENCH_N {
black_box(rng.gen::<usize>());
}
});
b.bytes = size_of::<usize>() as u64 * RAND_BENCH_N;
}

#[bench]
fn rand_isaac(b: &mut Bencher) {
let mut rng: IsaacRng = OsRng::new().unwrap().gen();
b.iter(|| {
for _ in 0..RAND_BENCH_N {
black_box(rng.gen::<usize>());
}
});
b.bytes = size_of::<usize>() as u64 * RAND_BENCH_N;
}

#[bench]
fn rand_isaac64(b: &mut Bencher) {
let mut rng: Isaac64Rng = OsRng::new().unwrap().gen();
b.iter(|| {
for _ in 0..RAND_BENCH_N {
black_box(rng.gen::<usize>());
}
});
b.bytes = size_of::<usize>() as u64 * RAND_BENCH_N;
}
use test::Bencher;
use rand::{weak_rng, Rng};

#[bench]
fn rand_std(b: &mut Bencher) {
let mut rng = StdRng::new().unwrap();
b.iter(|| {
for _ in 0..RAND_BENCH_N {
black_box(rng.gen::<usize>());
}
});
b.bytes = size_of::<usize>() as u64 * RAND_BENCH_N;
}
pub const RAND_BENCH_N: u64 = 100;

#[bench]
fn rand_shuffle_100(b: &mut Bencher) {
let mut rng = weak_rng();
let x : &mut [usize] = &mut [1; 100];
b.iter(|| {
rng.shuffle(x);
rng.shuffle(x)
})
}

mod algorithms {
use test::{black_box, Bencher};
use std::mem::size_of;
use rand::{OsRng, StdRng, weak_rng, XorShiftRng, XorShiftPlusRng, IsaacRng, Isaac64Rng, Rng, ChaChaRng};

use super::*;

macro_rules! impl_bench {
($result_ty: ty: $fn_name: ident, $hasher: ident) => (
#[bench]
fn $fn_name(b: &mut Bencher) {
let mut rng: $hasher = OsRng::new().unwrap().gen();
b.iter(|| {
for _ in 0..RAND_BENCH_N {
black_box(rng.gen::<$result_ty>());
}
});
b.bytes = size_of::<$result_ty>() as u64 * RAND_BENCH_N;
}
)
}

impl_bench!(u32: rand_xorshift_u32, XorShiftRng);
impl_bench!(u64: rand_xorshift_u64, XorShiftRng);
impl_bench!(u32: rand_rand_xorshiftplus_u32, XorShiftPlusRng);
impl_bench!(u64: rand_xorshiftplus_u64, XorShiftPlusRng);
impl_bench!(u32: rand_isaac_u32, IsaacRng);
impl_bench!(u64: rand_isaac_u64, IsaacRng);
impl_bench!(u32: rand_isaac64_u32, Isaac64Rng);
impl_bench!(u64: rand_isaac64_u64, Isaac64Rng);
impl_bench!(u32: rand_chacha_u32, ChaChaRng);
impl_bench!(u64: rand_chacha_u64, ChaChaRng);

#[bench]
fn rand_std(b: &mut Bencher) {
let mut rng = StdRng::new().unwrap();
b.iter(|| {
for _ in 0..RAND_BENCH_N {
black_box(rng.gen::<usize>());
}
});
b.bytes = size_of::<usize>() as u64 * RAND_BENCH_N;
}

#[bench]
fn rand_weak(b: &mut Bencher) {
let mut rng = weak_rng();
b.iter(|| {
for _ in 0..RAND_BENCH_N {
black_box(rng.gen::<usize>());
}
});
b.bytes = size_of::<usize>() as u64 * RAND_BENCH_N;
}
}
89 changes: 2 additions & 87 deletions src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -254,6 +254,7 @@ pub use os::OsRng;

pub use isaac::{IsaacRng, Isaac64Rng};
pub use chacha::ChaChaRng;
pub use xorshift::{XorShiftRng, XorShiftPlusRng};

#[cfg(target_pointer_width = "32")]
use IsaacRng as IsaacWordRng;
Expand All @@ -266,6 +267,7 @@ use distributions::range::SampleRange;
pub mod distributions;
pub mod isaac;
pub mod chacha;
pub mod xorshift;
pub mod reseeding;
mod rand_impls;
pub mod os;
Expand Down Expand Up @@ -598,93 +600,6 @@ pub trait SeedableRng<Seed>: Rng {
fn from_seed(seed: Seed) -> Self;
}

/// An Xorshift[1] random number
/// generator.
///
/// The Xorshift algorithm is not suitable for cryptographic purposes
/// but is very fast. If you do not know for sure that it fits your
/// requirements, use a more secure one such as `IsaacRng` or `OsRng`.
///
/// [1]: Marsaglia, George (July 2003). ["Xorshift
/// RNGs"](http://www.jstatsoft.org/v08/i14/paper). *Journal of
/// Statistical Software*. Vol. 8 (Issue 14).
#[allow(missing_copy_implementations)]
#[derive(Clone)]
pub struct XorShiftRng {
x: w32,
y: w32,
z: w32,
w: w32,
}

impl XorShiftRng {
/// Creates a new XorShiftRng instance which is not seeded.
///
/// The initial values of this RNG are constants, so all generators created
/// by this function will yield the same stream of random numbers. It is
/// highly recommended that this is created through `SeedableRng` instead of
/// this function
pub fn new_unseeded() -> XorShiftRng {
XorShiftRng {
x: w(0x193a6754),
y: w(0xa8a7d469),
z: w(0x97830e05),
w: w(0x113ba7bb),
}
}
}

impl Rng for XorShiftRng {
#[inline]
fn next_u32(&mut self) -> u32 {
let x = self.x;
let t = x ^ (x << 11);
self.x = self.y;
self.y = self.z;
self.z = self.w;
let w_ = self.w;
self.w = w_ ^ (w_ >> 19) ^ (t ^ (t >> 8));
self.w.0
}
}

impl SeedableRng<[u32; 4]> for XorShiftRng {
/// Reseed an XorShiftRng. This will panic if `seed` is entirely 0.
fn reseed(&mut self, seed: [u32; 4]) {
assert!(!seed.iter().all(|&x| x == 0),
"XorShiftRng.reseed called with an all zero seed.");

self.x = w(seed[0]);
self.y = w(seed[1]);
self.z = w(seed[2]);
self.w = w(seed[3]);
}

/// Create a new XorShiftRng. This will panic if `seed` is entirely 0.
fn from_seed(seed: [u32; 4]) -> XorShiftRng {
assert!(!seed.iter().all(|&x| x == 0),
"XorShiftRng::from_seed called with an all zero seed.");

XorShiftRng {
x: w(seed[0]),
y: w(seed[1]),
z: w(seed[2]),
w: w(seed[3]),
}
}
}

impl Rand for XorShiftRng {
fn rand<R: Rng>(rng: &mut R) -> XorShiftRng {
let mut tuple: (u32, u32, u32, u32) = rng.gen();
while tuple == (0, 0, 0, 0) {
tuple = rng.gen();
}
let (x, y, z, w_) = tuple;
XorShiftRng { x: w(x), y: w(y), z: w(z), w: w(w_) }
}
}

/// A wrapper for generating floating point numbers uniformly in the
/// open interval `(0,1)` (not including either endpoint).
///
Expand Down
Loading