86 lines
2.1 KiB
Rust
86 lines
2.1 KiB
Rust
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// cargo run --example upstream_benchmark --release
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use rand::{Rng, SeedableRng};
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const SAMPLES: usize = 10000;
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const ITERATIONS: usize = 1000;
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struct MeanAndVariance {
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n: i64,
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mean: f64,
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m2: f64,
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}
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impl MeanAndVariance {
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fn new() -> Self {
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MeanAndVariance {
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n: 0,
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mean: 0.0,
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m2: 0.0,
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}
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}
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fn update(&mut self, x: f64) {
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self.n += 1;
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let d = x - self.mean;
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self.mean += d / self.n as f64;
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let d2 = x - self.mean;
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self.m2 += d * d2;
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}
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fn variance(&self) -> f64 {
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self.m2 / (self.n - 1) as f64
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}
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fn stddev(&self) -> f64 {
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self.variance().sqrt()
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}
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}
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macro_rules! benchmark {
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($name:ident, $ty:ident) => {
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fn $name() -> usize {
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let mut rng = rand_xorshift::XorShiftRng::from_seed([123u8; 16]);
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let mut mv = MeanAndVariance::new();
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let mut throwaway = 0;
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for _ in 0..SAMPLES {
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let f = loop {
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let f = $ty::from_bits(rng.gen());
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if f.is_finite() {
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break f;
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}
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};
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let t1 = std::time::SystemTime::now();
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for _ in 0..ITERATIONS {
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throwaway += ryu::Buffer::new().format_finite(f).len();
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}
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let duration = t1.elapsed().unwrap();
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let nanos = duration.as_secs() * 1_000_000_000 + duration.subsec_nanos() as u64;
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mv.update(nanos as f64 / ITERATIONS as f64);
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}
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println!(
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"{:12} {:8.3} {:8.3}",
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concat!(stringify!($name), ":"),
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mv.mean,
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mv.stddev(),
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);
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throwaway
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}
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};
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}
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benchmark!(pretty32, f32);
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benchmark!(pretty64, f64);
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fn main() {
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println!("{:>20}{:>9}", "Average", "Stddev");
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let mut throwaway = 0;
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throwaway += pretty32();
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throwaway += pretty64();
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if std::env::var_os("ryu-benchmark").is_some() {
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// Prevent the compiler from optimizing the code away.
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println!("{}", throwaway);
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}
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}
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