Change API: Take only one interval at init

Cargo.toml

@@ -12,10 +12,6 @@ keywords = ["distributed"]
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
-[dependencies]
-anyhow = "1"
-thiserror = "1"
-
 [dev-dependencies]
 proptest = "1.4"
 tokio = { version = "1", features = ["full"] }

src/lib.rs

@@ -13,10 +13,10 @@
 //! use phi_detector::PingWindow;
 //! use std::time::Duration;
 //!
-//! // Create a window with intervals [100ms, 150ms].
-//! let initial_intervals = [Duration::from_millis(100), Duration::from_millis(150)];
-//! let mut window = PingWindow::new(&initial_intervals).unwrap();
+//! // Create a window with intervals 100ms.
+//! let mut window = PingWindow::new(Duration::from_millis(100));
 //!
+//! window.add_ping(Duration::from_millis(150));
 //! window.add_ping(Duration::from_millis(80));
 //! // Now the window has intervals [100ms, 150ms, 80ms]. Average is 110ms.
 //!
@@ -28,13 +28,7 @@
 //! }
 //! ```
 
-use std::time::{Duration, Instant};
-
-#[derive(thiserror::Error, Debug)]
-pub enum Error {
- #[error("No interval exists. At least one interval is required")]
- NoIntervals,
-}
+use std::time::Duration;
 
 fn phi_from_prob(x: f64) -> f64 {
  -f64::log10(x)
@@ -47,28 +41,17 @@ pub struct PingWindow {
  sum2: f64,
 }
 impl PingWindow {
- /// Create a new instance.
- /// `intervals` is the set of recent N ping intervals where N > 0.
- pub fn new(intervals: &[Duration]) -> Result<Self, Error> {
- let n = intervals.len();
- if n == 0 {
- return Err(Error::NoIntervals);
- }
-
- let mut sum = 0.;
- for &x in intervals {
- sum += x.as_millis() as f64;
+ /// Create a new instance with one reference interval.
+ pub fn new(interval: Duration) -> Self {
+ let sum = interval.as_millis() as f64;
+ Self {
+ n: 1,
+ sum,
+ sum2: 0.,
  }
- let mean = sum / n as f64;
- let mut sum2 = 0.;
- for &x in intervals {
- let d = x.as_millis() as f64 - mean;
- sum2 += d * d;
- }
- Ok(Self { n: 1, sum, sum2 })
  }
 
- /// Add new ping to the window.
+ /// Add a new ping to the window.
  pub fn add_ping(&mut self, du: Duration) {
  // Window size too large is found meaningless in experiment.
  // not only that, may harm by counting in old values. (e.g. latency change, overflow)
@@ -142,9 +125,11 @@ impl NormalDist {
 mod tests {
  use super::*;
 
+ use std::time::Instant;
+
  #[tokio::test]
- async fn test_phi_detector() -> anyhow::Result<()> {
- let mut window = PingWindow::new(&[Duration::from_secs(5)])?;
+ async fn test_phi_detector() {
+ let mut window = PingWindow::new(Duration::from_secs(5));
  for _ in 0..100 {
  window.add_ping(Duration::from_millis(100));
  }
@@ -159,18 +144,14 @@ mod tests {
  }
  tokio::time::sleep(Duration::from_millis(10)).await;
  }
-
- Ok(())
  }
 
  #[test]
- fn test_values() -> anyhow::Result<()> {
- let window = PingWindow::new(&[Duration::from_secs(5)])?;
+ fn test_values() {
+ let window = PingWindow::new(Duration::from_secs(5));
  let dist = window.normal_dist();
  dbg!(dist.mu());
  dbg!(dist.sigma());
-
- Ok(())
  }
 
  use proptest::prelude::*;