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rand 0.3.20

Random number generators and other randomness functionality.
Documentation 
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#![feature(test)]

extern crate test;
extern crate rand;

const RAND_BENCH_N: u64 = 1000;

mod distributions;

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

#[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_f32(b: &mut Bencher) {
    let mut rng = StdRng::new().unwrap();
    b.iter(|| {
        for _ in 0..RAND_BENCH_N {
            black_box(rng.next_f32());
        }
    });
    b.bytes = size_of::<f32>() as u64 * RAND_BENCH_N;
}

#[bench]
fn rand_f64(b: &mut Bencher) {
    let mut rng = StdRng::new().unwrap();
    b.iter(|| {
        for _ in 0..RAND_BENCH_N {
            black_box(rng.next_f64());
        }
    });
    b.bytes = size_of::<f64>() as u64 * RAND_BENCH_N;
}

#[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);
    })
}

#[bench]
fn rand_sample_10_of_100(b: &mut Bencher) {
    let mut rng = weak_rng();
    let x : &[usize] = &[1; 100];
    b.iter(|| {
        sample(&mut rng, x, 10);
    })
}