Struct TruthValue 

pub struct TruthValue {
    pub strength: f64,
    pub confidence: f64,
}

PLN indefinite truth value: (strength, confidence).

• strength — probability estimate ∈ [0, 1]
• confidence — certainty in the strength estimate ∈ [0, 1] (0 = no information, 1 = complete certainty)

Fields

strength: f64

Probability estimate.

confidence: f64

Confidence in the strength estimate.

Implementations

impl TruthValue

pub fn new(strength: f64, confidence: f64) -> Self

Create a new truth value, clamping both components to [0, 1].

pub fn unknown() -> Self

Return the unknown truth value (strength = 0.5, confidence = 0).

pub fn certain_true() -> Self

Return the true truth value (strength = 1, confidence = 1).

pub fn certain_false() -> Self

Return the false truth value (strength = 0, confidence = 1).

pub fn count(self) -> f64

Effective sample count n = c / (1 − c). Returns f64::INFINITY when confidence == 1.

pub fn negate(self) -> Self

PLN negation: NOT A.

pub fn conjunction(self, other: Self) -> Self

PLN conjunction: A AND B.

pub fn disjunction(self, other: Self) -> Self

PLN disjunction: A OR B.

pub fn revise(self, other: Self) -> Self

PLN revision: merge two independent estimates of the same proposition.

Uses weighted average by effective sample count:

s_rev = (s1 * n1 + s2 * n2) / (n1 + n2)
c_rev = (n1 + n2) / (n1 + n2 + 1)

pub fn deduction(ab: Self, bc: Self, b: Self, c: Self) -> Self

PLN deduction: given A→B and B→C, infer A→C.

s_AC = s_AB * s_BC + (1 − s_AB) * (s_C − s_B * s_BC) / (1 − s_B)
c_AC = c_AB * c_BC * min(1, c_AB * c_BC)

pub fn induction(ab: Self, ac: Self) -> Self

PLN induction: given A→B and A→C, infer B→C.

Simplified formula:

s_BC = s_AC / max(s_AB, 0.01), clamped [0, 1]
c_BC = c_AB * c_AC * min(1, c_AB * c_AC)

pub fn abduction(ba: Self, ca: Self) -> Self

PLN abduction: given B→A and C→A, infer B→C.

Dual of induction (swap roles of B and C):

s_BC = s_BA * s_CA / max(s_A, 0.01), clamped [0, 1]  (simplified)
c_BC = c_BA * c_CA * min(1, c_BA * c_CA)

pub fn modus_ponens(a: Self, ab: Self) -> Self

PLN Modus Ponens: given A (premise) and A→B (implication), infer B.

s_B  = s_A * s_AB + (1 − s_A) * (1 − s_AB) * 0.5   (mixture)
c_B  = c_A * c_AB

Trait Implementations

impl Clone for TruthValue

fn clone(&self) -> TruthValue

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TruthValue

impl Debug for TruthValue

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

Formats the value using the given formatter.

impl Default for TruthValue

fn default() -> Self

Returns the “default value” for a type.

impl Display for TruthValue

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

Formats the value using the given formatter.

impl PartialEq for TruthValue

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for TruthValue