Struct Trend 

pub struct Trend<const N: usize> { /* private fields */ }

Tracks the linear trend of the most recent N readings.

Is a value rising or falling, and how fast? A Trend fits a least-squares straight line to the last N readings, taken as evenly spaced in time, and reports its slope in units per sample: positive when rising, negative when falling, near zero when flat. Because the fit uses the whole window, a single noisy reading does not masquerade as a trend the way a bare difference between two samples can. The slope is the ordinary least-squares estimate, the sum of (x - mean_x) * (y - mean_y) over the sum of (x - mean_x) squared, with x taken as the sample index 0, 1, 2, and so on.

Examples

use pamoja_kit::Trend;

// A tank level falling two units per reading.
let mut level = Trend::<4>::new();
for reading in [40.0, 38.0, 36.0, 34.0] {
    level.push(reading);
}
assert!((level.slope().unwrap() + 2.0).abs() < 1e-4);

Implementations

impl<const N: usize> Trend<N>

pub fn new() -> Self

Creates an empty trend tracker over a window of N readings.

Returns

A tracker holding no readings yet.

pub fn push(&mut self, reading: f32)

Adds a reading, evicting the oldest once the window is full.

Arguments

• reading - the latest reading, taken one sample interval after the previous one.

pub fn slope(&self) -> Option<f32>

Returns the trend slope in units per sample, or None with fewer than two readings.

Returns

The least-squares slope of the window: positive when rising, negative when falling. None until at least two readings are present, since a single point has no slope.

pub fn len(&self) -> usize

Returns the number of readings currently held, at most N.

pub fn is_empty(&self) -> bool

Returns true if the tracker holds no readings.

Trait Implementations

impl<const N: usize> Clone for Trend<N>

fn clone(&self) -> Trend<N>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<const N: usize> Copy for Trend<N>

impl<const N: usize> Debug for Trend<N>

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

Formats the value using the given formatter.

impl<const N: usize> Default for Trend<N>

fn default() -> Self

Returns the “default value” for a type.