Trait TrainingCallback 

pub trait TrainingCallback: Send + Sync {
    // Required method
    fn on_epoch_end(&mut self, metrics: &EpochMetrics) -> CallbackAction;

    // Provided method
    fn on_training_end(&mut self) { ... }
}

Trait for user-supplied training callbacks.

Implement this to add custom logging, checkpointing, or stopping criteria during training.

Example

struct PrintLogger;

impl TrainingCallback for PrintLogger {
    fn on_epoch_end(&mut self, metrics: &EpochMetrics) -> CallbackAction {
        println!("Epoch {}: loss={:.4}", metrics.epoch, metrics.train_loss);
        CallbackAction::Continue
    }
}

Required Methods

fn on_epoch_end(&mut self, metrics: &EpochMetrics) -> CallbackAction

Called at the end of each training epoch.

Return CallbackAction::Stop to halt training early.

Provided Methods

fn on_training_end(&mut self)

Called when training finishes (after the last epoch).

Default implementation does nothing.

Implementors