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#![allow(deprecated)]
use criterion::{criterion_group, BenchmarkId, Criterion, Fun, ParameterizedBenchmark};
fn fibonacci_slow(n: u64) -> u64 {
match n {
0 | 1 => 1,
n => fibonacci_slow(n - 1) + fibonacci_slow(n - 2),
}
}
fn fibonacci_fast(n: u64) -> u64 {
let mut a = 0;
let mut b = 1;
match n {
0 => b,
_ => {
for _ in 0..n {
let c = a + b;
a = b;
b = c;
}
b
}
}
}
fn compare_fibonaccis(c: &mut Criterion) {
let fib_slow = Fun::new("Recursive", |b, i| b.iter(|| fibonacci_slow(*i)));
let fib_fast = Fun::new("Iterative", |b, i| b.iter(|| fibonacci_fast(*i)));
let functions = vec![fib_slow, fib_fast];
c.bench_functions("Fibonacci", functions, 20);
}
fn compare_fibonaccis_builder(c: &mut Criterion) {
c.bench(
"Fibonacci2",
ParameterizedBenchmark::new(
"Recursive",
|b, i| b.iter(|| fibonacci_slow(*i)),
vec![20u64, 21u64],
)
.with_function("Iterative", |b, i| b.iter(|| fibonacci_fast(*i))),
);
}
fn compare_fibonaccis_group(c: &mut Criterion) {
let mut group = c.benchmark_group("Fibonacci3");
for i in 20..=21 {
group.bench_with_input(BenchmarkId::new("Recursive", i), &i, |b, i| {
b.iter(|| fibonacci_slow(*i))
});
group.bench_with_input(BenchmarkId::new("Iterative", i), &i, |b, i| {
b.iter(|| fibonacci_fast(*i))
});
}
group.finish()
}
fn compare_looped(c: &mut Criterion) {
use criterion::black_box;
c.bench(
"small",
ParameterizedBenchmark::new("unlooped", |b, i| b.iter(|| i + 10), vec![10]).with_function(
"looped",
|b, i| {
b.iter(|| {
for _ in 0..10_000 {
black_box(i + 10);
}
})
},
),
);
}
criterion_group!(
fibonaccis,
compare_fibonaccis,
compare_fibonaccis_builder,
compare_fibonaccis_group,
compare_looped
);
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