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use criterion::{criterion_group, criterion_main, Criterion};
use itertools::{Itertools, cloned};
trait IterEx : Iterator {
// Another efficient implementation against which to compare,
// but needs `std` so is less desirable.
fn tree_fold1_vec<F>(self, mut f: F) -> Option<Self::Item>
where F: FnMut(Self::Item, Self::Item) -> Self::Item,
Self: Sized,
{
let hint = self.size_hint().0;
let cap = std::mem::size_of::<usize>() * 8 - hint.leading_zeros() as usize;
let mut stack = Vec::with_capacity(cap);
self.enumerate().for_each(|(mut i, mut x)| {
while (i & 1) != 0 {
x = f(stack.pop().unwrap(), x);
i >>= 1;
}
stack.push(x);
});
stack.into_iter().fold1(f)
}
}
impl<T:Iterator> IterEx for T {}
macro_rules! def_benchs {
($N:expr,
$FUN:ident,
$BENCH_NAME:ident,
) => (
mod $BENCH_NAME {
use super::*;
pub fn sum(c: &mut Criterion) {
let v: Vec<u32> = (0.. $N).collect();
c.bench_function(&(stringify!($BENCH_NAME).replace('_', " ") + " sum"), move |b| {
b.iter(|| {
cloned(&v).$FUN(|x, y| x + y)
})
});
}
pub fn complex_iter(c: &mut Criterion) {
let u = (3..).take($N / 2);
let v = (5..).take($N / 2);
let it = u.chain(v);
c.bench_function(&(stringify!($BENCH_NAME).replace('_', " ") + " complex iter"), move |b| {
b.iter(|| {
it.clone().map(|x| x as f32).$FUN(f32::atan2)
})
});
}
pub fn string_format(c: &mut Criterion) {
// This goes quadratic with linear `fold1`, so use a smaller
// size to not waste too much time in travis. The allocations
// in here are so expensive anyway that it'll still take
// way longer per iteration than the other two benchmarks.
let v: Vec<u32> = (0.. ($N/4)).collect();
c.bench_function(&(stringify!($BENCH_NAME).replace('_', " ") + " string format"), move |b| {
b.iter(|| {
cloned(&v).map(|x| x.to_string()).$FUN(|x, y| format!("{} + {}", x, y))
})
});
}
}
criterion_group!(
$BENCH_NAME,
$BENCH_NAME::sum,
$BENCH_NAME::complex_iter,
$BENCH_NAME::string_format,
);
)
}
def_benchs!{
10_000,
fold1,
fold1_10k,
}
def_benchs!{
10_000,
tree_fold1,
tree_fold1_stack_10k,
}
def_benchs!{
10_000,
tree_fold1_vec,
tree_fold1_vec_10k,
}
def_benchs!{
100,
fold1,
fold1_100,
}
def_benchs!{
100,
tree_fold1,
tree_fold1_stack_100,
}
def_benchs!{
100,
tree_fold1_vec,
tree_fold1_vec_100,
}
def_benchs!{
8,
fold1,
fold1_08,
}
def_benchs!{
8,
tree_fold1,
tree_fold1_stack_08,
}
def_benchs!{
8,
tree_fold1_vec,
tree_fold1_vec_08,
}
criterion_main!(
fold1_10k,
tree_fold1_stack_10k,
tree_fold1_vec_10k,
fold1_100,
tree_fold1_stack_100,
tree_fold1_vec_100,
fold1_08,
tree_fold1_stack_08,
tree_fold1_vec_08,
);