Module path_quality 

Path Quality Computation

Implements TPO (Topological Preference Optimization) path quality scoring for enhanced salience computation. Quality measures how “good” a conversation path is, which helps weight turns within that path.

Path Quality Formula

Q(P) = α·L(P) + β·T(P) + γ·S(P) + δ·C(P)

Factor	Formula	Meaning	Default Weight
L(P)	1 - var(depth_changes)	Linearity - smooth depth progression	α = 0.25
T(P)	terminal_node_score	Terminal quality - how path ends	β = 0.30
S(P)	mean(homogeneity)	Semantic coherence along path	γ = 0.25
C(P)	path_length / max_length	Completion - path reaches conclusion	δ = 0.20

Usage

use rag_plusplus_core::trajectory::{PathQuality, PathQualityWeights, PathQualityFactors};

// Compute factors for a path
let factors = PathQualityFactors::from_path_data(
    &[1, 2, 3, 4],           // depths along path
    &[0.9, 0.85, 0.8, 0.75], // homogeneity values
    5,                        // max possible depth
    true,                     // is terminal
    0.8,                      // terminal score if terminal
);

// Compute quality score with default weights
let quality = factors.compute_quality(&PathQualityWeights::default());

// Use for salience enhancement
let base_salience = 0.5;
let enhanced_salience = PathQuality::enhance_salience(base_salience, quality, 0.3);

Structs

PathQuality

Path quality utilities.

PathQualityFactors

Computed path quality factors.

PathQualityWeights

Weights for path quality components.