rust/src/test/bench/shootout-spectralnorm.rs
2014-03-24 17:17:46 -07:00

114 lines
3.2 KiB
Rust

// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
extern crate sync;
use std::from_str::FromStr;
use std::iter::count;
use std::cmp::min;
use std::os;
use std::slice::from_elem;
use sync::{Arc, RWLock};
fn A(i: uint, j: uint) -> f64 {
((i + j) * (i + j + 1) / 2 + i + 1) as f64
}
fn dot(v: &[f64], u: &[f64]) -> f64 {
let mut sum = 0.0;
for (&v_i, &u_i) in v.iter().zip(u.iter()) {
sum += v_i * u_i;
}
sum
}
fn mult(v: Arc<RWLock<Vec<f64>>>, out: Arc<RWLock<Vec<f64>>>,
f: fn(&Vec<f64>, uint) -> f64) {
// We lanch in different tasks the work to be done. To finish
// this fuction, we need to wait for the completion of every
// tasks. To do that, we give to each tasks a wait_chan that we
// drop at the end of the work. At the end of this function, we
// wait until the channel hang up.
let (tx, rx) = channel();
let len = out.read().len();
let chunk = len / 100 + 1;
for chk in count(0, chunk) {
if chk >= len {break;}
let tx = tx.clone();
let v = v.clone();
let out = out.clone();
spawn(proc() {
for i in range(chk, min(len, chk + chunk)) {
let val = f(&*v.read(), i);
*out.write().get_mut(i) = val;
}
drop(tx)
});
}
// wait until the channel hang up (every task finished)
drop(tx);
for () in rx.iter() {}
}
fn mult_Av_impl(v: &Vec<f64> , i: uint) -> f64 {
let mut sum = 0.;
for (j, &v_j) in v.iter().enumerate() {
sum += v_j / A(i, j);
}
sum
}
fn mult_Av(v: Arc<RWLock<Vec<f64>>>, out: Arc<RWLock<Vec<f64>>>) {
mult(v, out, mult_Av_impl);
}
fn mult_Atv_impl(v: &Vec<f64> , i: uint) -> f64 {
let mut sum = 0.;
for (j, &v_j) in v.iter().enumerate() {
sum += v_j / A(j, i);
}
sum
}
fn mult_Atv(v: Arc<RWLock<Vec<f64>>>, out: Arc<RWLock<Vec<f64>>>) {
mult(v, out, mult_Atv_impl);
}
fn mult_AtAv(v: Arc<RWLock<Vec<f64>>>, out: Arc<RWLock<Vec<f64>>>,
tmp: Arc<RWLock<Vec<f64>>>) {
mult_Av(v, tmp.clone());
mult_Atv(tmp, out);
}
fn main() {
let args = os::args();
let n = if os::getenv("RUST_BENCH").is_some() {
5500
} else if args.len() < 2 {
2000
} else {
FromStr::from_str(args[1]).unwrap()
};
let u = Arc::new(RWLock::new(Vec::from_elem(n, 1.)));
let v = Arc::new(RWLock::new(Vec::from_elem(n, 1.)));
let tmp = Arc::new(RWLock::new(Vec::from_elem(n, 1.)));
for _ in range(0, 10) {
mult_AtAv(u.clone(), v.clone(), tmp.clone());
mult_AtAv(v.clone(), u.clone(), tmp.clone());
}
let u = u.read();
let v = v.read();
println!("{:.9f}", (dot(u.as_slice(), v.as_slice()) /
dot(v.as_slice(), v.as_slice())).sqrt());
}