Struct Evidence 

pub struct Evidence { /* private fields */ }

The accumulated evidence for one relationship: the pseudo-counts of its Beta posterior.

alpha counts corroboration, beta counts contradiction. Both are weighted sums, not integers — an observation contributes its provenance weight. Counts are non-negative by construction.

Implementations

impl Evidence

pub fn from_prior(mean: f64) -> Self

Evidence for an edge that has only a mean: split PRIOR_CONCENTRATION between the two counts so the mean is preserved exactly.

This is the shape a brand-new edge starts in, and the shape the schema migration backfills legacy edges into.

pub fn from_counts(alpha: f64, beta: f64) -> Self

Evidence from persisted counts. Non-finite or negative counts are clamped to zero — a corrupt count must not produce a nonsense mean.

pub fn from_stored( alpha: Option<f64>, beta: Option<f64>, confidence: f64, ) -> Self

Evidence for an edge as read from the store.

Uses the persisted counts when present; falls back to Evidence::from_prior over the stored mean when they are absent — the shape of an edge on a store whose migration has not run yet.

pub fn corroborate(&mut self, weight: f64)

Record supporting evidence of the given weight.

pub fn contradict(&mut self, weight: f64)

Record contradicting evidence of the given weight.

pub fn alpha(self) -> f64

Corroboration pseudo-count.

pub fn beta(self) -> f64

Contradiction pseudo-count.

pub fn concentration(self) -> f64

Total evidence weight behind this edge (alpha + beta).

This is what never grew in the pre-Phase-1 model: it is the difference between “believed at 0.9” and “believed at 0.9 for good reason”.

pub fn mean(self) -> f64

Posterior mean — the value stored as the edge’s confidence.

With no evidence in either direction the mean is 0.5 (maximal ignorance).

pub fn variance(self) -> f64

Posterior variance — αβ / ((α+β)²(α+β+1)).

Strictly decreasing in the amount of evidence at a fixed mean, which is how “corroborated fifty times” is told apart from “corroborated once”.

Trait Implementations

impl Clone for Evidence

fn clone(&self) -> Evidence

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Evidence

impl Debug for Evidence

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

Formats the value using the given formatter.

impl PartialEq for Evidence

fn eq(&self, other: &Evidence) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Evidence