Crate frequenz_resampling 

frequenz-resampling-rs

This project is the rust resampler for resampling a stream of samples to a given interval.

Usage

An instance of the Resampler can be created with the new method. Raw data can be added to the resampler either through the push or extend methods, and the resample method resamples the data that was added to the buffer.

use chrono::{DateTime, TimeDelta, Utc};
use frequenz_resampling::{Closed, Label, Resampler, ResamplingFunction, Sample};

#[derive(Debug, Clone, Default, Copy, PartialEq)]
pub(crate) struct TestSample {
    timestamp: DateTime<Utc>,
    value: Option<f64>,
}

impl Sample for TestSample {
    type Value = f64;

    fn new(timestamp: DateTime<Utc>, value: Option<f64>) -> Self {
        Self { timestamp, value }
    }

    fn timestamp(&self) -> DateTime<Utc> {
        self.timestamp
    }

    fn value(&self) -> Option<f64> {
        self.value
    }
}

let start = DateTime::from_timestamp(0, 0).unwrap();
let mut resampler: Resampler<f64, TestSample> =
    Resampler::new(
        TimeDelta::seconds(5),
        ResamplingFunction::Average,
        1,
        start,
        Closed::Left,
        Label::Right,
    );

let step = TimeDelta::seconds(1);
// Data starts at t=0 with values 1-10
// Interval [0, 5): t=0,1,2,3,4 with values 1,2,3,4,5 → avg = 3.0
// Interval [5, 10): t=5,6,7,8,9 with values 6,7,8,9,10 → avg = 8.0
let data = vec![
    TestSample::new(start, Some(1.0)),
    TestSample::new(start + step, Some(2.0)),
    TestSample::new(start + step * 2, Some(3.0)),
    TestSample::new(start + step * 3, Some(4.0)),
    TestSample::new(start + step * 4, Some(5.0)),
    TestSample::new(start + step * 5, Some(6.0)),
    TestSample::new(start + step * 6, Some(7.0)),
    TestSample::new(start + step * 7, Some(8.0)),
    TestSample::new(start + step * 8, Some(9.0)),
    TestSample::new(start + step * 9, Some(10.0)),
];

resampler.extend(data);

let resampled = resampler.resample(start + step * 10);

let expected = vec![
    TestSample::new(DateTime::from_timestamp(5, 0).unwrap(), Some(3.0)),
    TestSample::new(DateTime::from_timestamp(10, 0).unwrap(), Some(8.0)),
];

assert_eq!(resampled, expected);

Structs

Resampler

The Resampler struct is used to resample a time series of samples. It stores the samples in a buffer and resamples the samples in the buffer when the resample method is called. A resampler can be configured with a resampling function and a resampling interval.

SimpleSample

A simple sample type for use with the resample function.

Enums

Closed

Controls which edge of an interval is closed for sample membership.

Label

Controls which edge of an interval is used as the output timestamp label.

ResamplingFunction

The ResamplingFunction enum represents the different resampling functions that can be used to resample a channel.

Traits

Sample

The Sample trait represents a single sample in a time series.

Functions

epoch_align

Aligns a timestamp to the epoch of the resampling interval.

resample

Resamples a list of timestamp/value pairs in a single call.