Struct DdmDetector 

pub struct DdmDetector<A: Float + Send + Sync> { /* private fields */ }

DDM (Drift Detection Method) detector.

C3: implemented per Gama et al., “Learning with Drift Detection” (2004). The detector tracks the online error rate p_i and its standard deviation s_i = sqrt(p_i (1 - p_i) / i), remembers the pair (p_min, s_min) observed at the minimum of p_i + s_i, and compares the current p_i + s_i against p_min + 2*s_min (warning) and p_min + 3*s_min (drift).

The previous implementation instead tracked min(p_i + 2*s_i) in min_error_plus_2_std and set min_error_plus_3_std to p_i + 3*s_i at that same moment. The published 2*s_min / 3*s_min margins were therefore never applied: the warning test degenerated to “is the current level above the smallest level ever seen”, which fires on essentially any upward noise, and the drift test compared p + 2s against p_min + 3*s_min where both terms came from different definitions. It also seeded error_std = 1.0, which is not a possible standard deviation for a rate in [0, 1].

Implementations

impl<A: Float + Send + Sync> DdmDetector<A>

pub const DEFAULT_WARMUP: usize = 30

Minimum samples before the DDM statistics are meaningful (the value used in the original paper).

pub fn new() -> Self

Create a new DDM detector

pub fn with_warmup(warmup: usize) -> Self

Create a DDM detector with a custom warm-up length.

pub fn error_rate(&self) -> A

Current error rate estimate.

pub fn warning_level(&self) -> Option<A>

Current warning level p_min + 2*s_min, if the baseline is established.

pub fn drift_level(&self) -> Option<A>

Current drift level p_min + 3*s_min, if the baseline is established.

pub fn update(&mut self, iserror: bool) -> DriftStatus

Update with prediction result

pub fn reset(&mut self)

Reset detector state

Trait Implementations

impl<A: Clone + Float + Send + Sync> Clone for DdmDetector<A>

fn clone(&self) -> DdmDetector<A>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<A: Debug + Float + Send + Sync> Debug for DdmDetector<A>

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

Formats the value using the given formatter.

impl<A: Float + Send + Sync> Default for DdmDetector<A>

fn default() -> Self

Returns the “default value” for a type.