Struct russell_lab::Stopwatch

pub struct Stopwatch { /* private fields */ }

Assists in measuring computation time

Examples

Printing elapsed times

use russell_lab::Stopwatch;
use std::thread::sleep;
use std::time::Duration;

fn expensive_calculation() {
    sleep(Duration::new(0, 1_000));
}

let mut sw = Stopwatch::new("current dt = ");
expensive_calculation();
sw.stop();
println!("{}", sw);

sw.reset();
expensive_calculation();
sw.stop();
println!("{}", sw);

sw.reset();
expensive_calculation();
sw.stop();
println!("{}", sw);

Recording elapsed times

use russell_lab::Stopwatch;
use std::thread::sleep;
use std::time::Duration;

fn expensive_calculation() {
    sleep(Duration::new(0, 1_000));
}

let mut elapsed_times = vec![0_u128; 3];
let mut sw = Stopwatch::new("");

expensive_calculation();
elapsed_times[0] = sw.stop_and_reset();

expensive_calculation();
elapsed_times[1] = sw.stop_and_reset();

expensive_calculation();
elapsed_times[2] = sw.stop_and_reset();

// println!("{:?}", elapsed_times); // will show something like:
// [57148, 55991, 55299]

Implementations

impl Stopwatch

pub fn new(label: &'static str) -> Self

Creates and starts a new Stopwatch

Input

label – used when displaying the elapsed time

Note

The method stop (or stop_and_reset) must be called to measure the elapsed time. Until then, the displayed elapsed time is zero, even though the stopwatch has already started.

Example

use russell_lab::Stopwatch;
let sw = Stopwatch::new("elapsed time = ");
assert_eq!(format!("{}", sw), "elapsed time = 0ns");

pub fn stop(&mut self) -> u128

Stops the stopwatch and returns the elapsed time

Output

Returns the elapsed time

Example

use russell_lab::Stopwatch;
use std::thread::sleep;
use std::time::Duration;
let mut sw = Stopwatch::new("");
sleep(Duration::new(0, 1_000));
let elapsed = sw.stop();
assert!(elapsed > 0);
// println!("{}", sw); // will show something like:
// 63.099µs

pub fn reset(&mut self)

Resets the stopwatch to zero elapsed time

Example

use russell_lab::Stopwatch;
use std::thread::sleep;
use std::time::Duration;
let mut sw = Stopwatch::new("delta_t = ");
sleep(Duration::new(0, 1_000));
sw.stop();
sw.reset();
assert_eq!(format!("{}", sw), "delta_t = 0ns");

pub fn stop_and_reset(&mut self) -> u128

Stops the stopwatch and resets it to zero elapsed time

Output

Returns the elapsed time

Example

use russell_lab::Stopwatch;
use std::thread::sleep;
use std::time::Duration;
let mut sw = Stopwatch::new("current = ");
sleep(Duration::new(0, 1_000));
let elapsed = sw.stop_and_reset();
// println!("{}", format_nanoseconds(elapsed)); // will show something like
// current = 63.099µs
assert!(elapsed > 0);
assert_eq!(format!("{}", sw), "current = 0ns");

Trait Implementations

impl Display for Stopwatch

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.