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extern crate num_traits;
use num_traits::{Float, NumCast};
pub struct MovingAverage<T> {
hist: Vec<T>,
size: T,
pos: usize,
}
impl<T: Float + NumCast> MovingAverage<T> {
pub fn new(size: usize) -> Self {
MovingAverage {
hist: vec![T::zero(); size],
size: T::from(size).unwrap(),
pos: 0,
}
}
pub fn feed(&mut self, num: T) -> T {
self.hist[self.pos] = num;
self.pos += 1;
self.pos %= self.hist.len();
self.avg()
}
fn avg(&self) -> T {
self.hist.iter().fold(T::zero(), |s, &x| s + x) / self.size
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_ma() {
let mut ma = MovingAverage::<f32>::new(10);
assert_eq!(ma.feed(1.0), 0.1);
assert_eq!(ma.feed(1.0), 0.2);
assert_eq!(ma.feed(1.0), 0.3);
assert_eq!(ma.feed(1.0), 0.4);
assert_eq!(ma.feed(1.0), 0.5);
assert_eq!(ma.feed(1.0), 0.6);
assert_eq!(ma.feed(1.0), 0.7);
assert_eq!(ma.feed(1.0), 0.8);
assert_eq!(ma.feed(1.0), 0.9);
assert_eq!(ma.feed(1.0), 1.0);
assert_eq!(ma.feed(0.0), 0.9);
assert_eq!(ma.feed(0.0), 0.8);
assert_eq!(ma.feed(0.0), 0.7);
assert_eq!(ma.feed(0.0), 0.6);
assert_eq!(ma.feed(0.0), 0.5);
assert_eq!(ma.feed(0.0), 0.4);
assert_eq!(ma.feed(0.0), 0.3);
assert_eq!(ma.feed(0.0), 0.2);
assert_eq!(ma.feed(0.0), 0.1);
assert_eq!(ma.feed(0.0), 0.0);
}
}