Source code for jz_python_chest.callback_example

# trainer callback example


class Callback:



    def on_train_begin(self, logs=None):
        pass




    def on_train_end(self, logs=None):
        pass




    def on_epoch_begin(self, epoch, logs=None):
        pass




    def on_train_step_end(self, step, logs=None):
        pass




    def on_train_epoch_end(self, epoch, logs=None):
        pass






class PrintStepCallback(Callback):



    def on_train_step_end(self, step, logs=None):
        print(f"Step {step} completed.")






class PrintEpochCallback(Callback):



    def on_train_epoch_end(self, epoch, logs=None):
        print(f"Epoch {epoch} completed.")






class PrintTrainBeginCallback(Callback):



    def on_train_begin(self, logs=None):
        print("Training started.")






class PrintTrainEndCallback(Callback):



    def on_train_end(self, logs=None):
        print("Training finished.")






class Trainer:

    def __init__(self, model, callbacks=None):
        self.model = model
        self.callbacks = callbacks or []



    def train(self, epochs, steps_per_epoch):
        logs = {}

        # Call on_train_begin callbacks
        for callback in self.callbacks:
            callback.on_train_begin(logs)

        for epoch in range(epochs):
            # Call on_epoch_begin callbacks
            for callback in self.callbacks:
                callback.on_epoch_begin(epoch, logs)

            for step in range(steps_per_epoch):
                # Simulate a training step
                self.model.train_step()

                # Call on_train_step_end callbacks
                for callback in self.callbacks:
                    callback.on_train_step_end(step, logs)

            # Call on_train_epoch_end callbacks
            for callback in self.callbacks:
                callback.on_train_epoch_end(epoch, logs)

        # Call on_train_end callbacks
        for callback in self.callbacks:
            callback.on_train_end(logs)




# Example model class


class Model:



    def train_step(self):
        pass  # Implement your training step logic here




if __name__ == '__main__':
    # Usage
    model = Model()
    callbacks = [
        PrintTrainBeginCallback(),
        PrintStepCallback(),
        PrintEpochCallback(),
        PrintTrainEndCallback()
    ]
    trainer = Trainer(model, callbacks)
    trainer.train(epochs=5, steps_per_epoch=10)