Struct BetaPosterior 

pub struct BetaPosterior {
    pub alpha: f64,
    pub beta: f64,
    pub n: u64,
    pub c_self: f64,
    pub kappa: f64,
    pub last_update: DateTime<Utc>,
}

Per-(agent, skill, bucket) Beta-Bernoulli posterior.

Keeps alpha and beta as f64 so the forgetting factor λ can apply continuous decay without losing resolution on small-count cells.

Fields

alpha: f64

Pseudo-count of observed successes (plus the weak prior).

beta: f64

Pseudo-count of observed failures (plus the weak prior).

n: u64

Total real observations seen so far.

c_self: f64

Self-declared prior confidence in [0, 1], used to seed alpha / beta on first touch.

kappa: f64

Weak-prior strength multiplier for Self::c_self.

last_update: DateTime<Utc>

Timestamp of the last update, for drift diagnostics.

Implementations

impl BetaPosterior

pub fn from_self_confidence(c_self: f64, kappa: f64) -> Self

Seed a fresh posterior from self-declared confidence.

pub fn mean(&self) -> f64

Posterior mean: μ = α / (α + β).

pub fn variance(&self) -> f64

Posterior variance: u = αβ / ((α+β)² (α+β+1)).

pub fn score(&self, gamma: f64) -> f64

LCB risk-aware score μ − γ · √u.

pub fn update(&mut self, outcome: bool, lambda: f64)

Apply an observed outcome. Forgetting factor lambda ∈ [0, 1] multiplicatively decays prior pseudo-counts before the update.

Trait Implementations

impl Clone for BetaPosterior

fn clone(&self) -> BetaPosterior

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BetaPosterior

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for BetaPosterior

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for BetaPosterior

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.