Trait MatrixHook

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pub trait MatrixHook: Send + Sync {
    // Required methods
    fn on_converge(
        &self,
        node_name: &str,
        actual_contribution: f64,
        surprise: f64,
        quality: f64,
    );
    fn route(&self, from: &str, candidates: &[String]) -> Option<Vec<String>>;
    fn c_value(&self) -> f64;
    fn completion(&self) -> f64;
    fn is_converged(&self) -> bool;
    fn record_transition(&self, from: &str, to: &str, quality: f64);
}

Expand description

Hook for the optional matrix layer.

Injected into the Pregel engine by pe-runtime when the matrix layer is active. The engine calls these methods at the right moments; the hook implementation does the actual convergence tracking and routing.

Send + Sync because the engine may run nodes in parallel.

§Thread safety

The hook is shared across the BSP loop (single-threaded per superstep) but must be Send + Sync to satisfy trait object requirements. Interior mutability (via Mutex) is expected since the BSP loop is sequential.

Required Methods§

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fn on_converge( &self, node_name: &str, actual_contribution: f64, surprise: f64, quality: f64, )

Called when a node returns NodeResult::Converge.

Records the convergence signal metadata. The engine has already extracted and applied the partial_update — this receives only the signal values (contribution, surprise, quality) and the originating node name.

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fn route(&self, from: &str, candidates: &[String]) -> Option<Vec<String>>

Resolve routing for a conditional edge using learned probabilities.

Called instead of the user’s router function when the matrix layer is active. from is the source node, candidates are the possible target nodes (from the conditional edge’s router output).

Returns the selected candidate(s). If this returns None, the engine falls back to the user’s router function (graceful degradation).

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