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shootout-mandelbrot rewrite

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- removed warning
- improved performances
- parallelization
This commit is contained in:
Guillaume Pinot 2014-05-03 14:53:52 +02:00
parent e0d261e576
commit 66b7c11c90
1 changed files with 55 additions and 58 deletions
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113
src/test/bench/shootout-mandelbrot.rs
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@ -1,4 +1,4 @@
// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
// 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.
//
@ -8,72 +8,69 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::io;
extern crate sync;
struct DummyWriter;
impl Writer for DummyWriter {
fn write(&mut self, _: &[u8]) -> io::IoResult<()> { Ok(()) }
}
use std::io;
use sync::Future;
static ITER: int = 50;
static LIMIT: f64 = 2.0;
fn main() {
let args = std::os::args();
let (w, mut out) = if args.len() < 2 {
println!("Test mode: do not dump the image because it's not utf8, \
which interferes with the test runner.");
(1000, ~DummyWriter as ~Writer)
} else {
(from_str(args[1]).unwrap(),
~std::io::stdout() as ~Writer)
};
let h = w;
let mut byte_acc = 0u8;
let mut bit_num = 0;
writeln!(out, "P4\n{} {}", w, h);
for y in range(0, h) {
let y = y as f64;
for x in range(0, w) {
let mut z_r = 0f64;
let mut z_i = 0f64;
let mut t_r = 0f64;
let mut t_i = 0f64;
let c_r = 2.0 * (x as f64) / (w as f64) - 1.5;
let c_i = 2.0 * (y as f64) / (h as f64) - 1.0;
fn write_line(init_i: f64, vec_init_r: &[f64], res: &mut Vec<u8>) {
for chunk_init_r in vec_init_r.chunks(8) {
let mut cur_byte = 0xff;
let mut cur_bitmask = 0x80;
for &init_r in chunk_init_r.iter() {
let mut cur_r = init_r;
let mut cur_i = init_i;
for _ in range(0, ITER) {
if t_r + t_i > LIMIT * LIMIT {
let r = cur_r;
let i = cur_i;
cur_r = r * r - i * i + init_r;
cur_i = 2.0 * r * i + init_i;
if r * r + i * i > LIMIT * LIMIT {
cur_byte &= !cur_bitmask;
break;
}
z_i = 2.0 * z_r * z_i + c_i;
z_r = t_r - t_i + c_r;
t_r = z_r * z_r;
t_i = z_i * z_i;
}
byte_acc <<= 1;
if t_r + t_i <= LIMIT * LIMIT {
byte_acc |= 1;
}
bit_num += 1;
if bit_num == 8 {
out.write_u8(byte_acc);
byte_acc = 0;
bit_num = 0;
} else if x == w - 1 {
byte_acc <<= 8 - w % 8;
out.write_u8(byte_acc);
byte_acc = 0;
bit_num = 0;
}
cur_bitmask >>= 1;
}
res.push(cur_byte);
}
out.flush();
}
fn mandelbrot<W: io::Writer>(w: uint, mut out: W) -> io::IoResult<()> {
// Ensure w and h are multiples of 8.
let w = (w + 7) / 8 * 8;
let h = w;
let chunk_size = h / 8;
let data: Vec<Future<Vec<u8>>> = range(0u, 8).map(|i| Future::spawn(proc () {
let vec_init_r = Vec::from_fn(w, |x| 2.0 * (x as f64) / (w as f64) - 1.5);
let mut res: Vec<u8> = Vec::with_capacity((chunk_size * w) / 8);
for y in range(i * chunk_size, (i + 1) * chunk_size) {
let init_i = 2.0 * (y as f64) / (h as f64) - 1.0;
write_line(init_i, vec_init_r.as_slice(), &mut res);
}
res
})).collect();
try!(writeln!(&mut out as &mut Writer, "P4\n{} {}", w, h));
for res in data.move_iter() {
try!(out.write(res.unwrap().as_slice()));
}
out.flush()
}
fn main() {
let args = std::os::args();
let res = if args.len() < 2 {
println!("Test mode: do not dump the image because it's not utf8, \
which interferes with the test runner.");
mandelbrot(1000, std::io::util::NullWriter)
} else {
mandelbrot(from_str(args[1]).unwrap(), std::io::stdout())
};
res.unwrap();
}