Struct FeatureDriftDetector 

pub struct FeatureDriftDetector<const D: usize> { /* private fields */ }

Per-dim histogram-driven feature drift detector.

D pins the feature-vector dimensionality at compile time, mirroring the rest of the crate. The detector is std-only because it ships its observability plumbing.

Implementations

impl<const D: usize> FeatureDriftDetector<D>

pub fn new(num_bins: usize) -> RcfResult<Self>

Build a fresh detector with num_bins equal-width bins per dimension. Uses DEFAULT_SMOOTHING for Laplace smoothing.

Errors

Returns RcfError::InvalidConfig when num_bins < 2 or D == 0.

pub fn with_smoothing(num_bins: usize, smoothing: f64) -> RcfResult<Self>

Like Self::new but with a caller-chosen smoothing epsilon in (0, 1].

Errors

Returns RcfError::InvalidConfig on any out-of-range argument.

pub fn with_metrics_sink(self, sink: Arc<dyn MetricsSink>) -> Self

Install a metrics sink — every observe / psi call emits counters/gauges into it.

pub fn metrics_sink(&self) -> &Arc<dyn MetricsSink>

Read-only handle to the installed sink.

pub fn is_baseline_frozen(&self) -> bool

Whether Self::freeze_baseline has been called.

pub fn observations_total(&self) -> u64

Lifetime count of Self::observe calls.

pub fn num_bins(&self) -> usize

Number of equal-width bins per dimension.

pub fn bin_edges(&self) -> Option<&[(f64, f64); D]>

Per-dim (min, max) range pinned at baseline time — None before Self::freeze_baseline.

pub fn observe(&mut self, point: &[f64; D]) -> RcfResult<()>

Fold point into the production histogram (or the pre- freeze buffer when the baseline has not yet been frozen).

Errors

• RcfError::NaNValue when point contains a non-finite component.

pub fn freeze_baseline(&mut self) -> RcfResult<()>

Freeze the current production histogram as the baseline. Computes per-dim (min, max) from the collected samples, rebuilds the histogram with equal-width bins, then clones it into the baseline slot. Subsequent Self::observe calls feed the production histogram only.

Errors

Returns RcfError::EmptyForest when no points have been observed yet (nothing to bin).

pub fn reset_production(&mut self)

Drop the production histogram; keep the baseline. Call between monitoring windows.

pub fn psi(&self) -> RcfResult<Vec<f64>>

Per-dim Population Stability Index against the baseline. Returns a Vec of length D; entry d is Σ_i (Q_i − P_i) · ln(Q_i / P_i) with Laplace smoothing.

Errors

Returns RcfError::EmptyForest when the baseline has not been frozen.

pub fn kl_divergence(&self) -> RcfResult<Vec<f64>>

Per-dim KL divergence D_KL(Q || P) against the baseline — Σ_i Q_i · ln(Q_i / P_i). Asymmetric; see module docs.

Errors

Returns RcfError::EmptyForest when the baseline has not been frozen.

pub fn max_psi(&self) -> RcfResult<f64>

Maximum PSI across every dimension — the single number SOC dashboards usually alert on.

Errors

Same as Self::psi.

pub fn argmax_psi(&self) -> RcfResult<Option<usize>>

Dim index with the largest PSI — useful for root-causing “which feature moved?”.

Errors

Same as Self::psi. Returns Ok(None) when every PSI is exactly zero.

Trait Implementations

impl<const D: usize> Debug for FeatureDriftDetector<D>

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

Formats the value using the given formatter.