Base callback

class argus.callbacks.Callback

Base callback class. All callbacks classes should inherit from this class.

A callback may execute actions on the start and the end of the whole training process, each epoch or iteration, as well as any other custom events.

The actions should be specified within corresponding methods that take the argus.engine.State as input:

• start: triggered when the training is started.

• complete: triggered when the training is completed.

• epoch_start: triggered when an epoch is started.

• epoch_complete: triggered when an epoch is ended.

• iteration_start: triggered when an iteration is started.

• iteration_complete: triggered when an iteration is ended.

• catch_exception: triggered on catching of an exception.

Example

A simple custom callback which stops training after the specified time:

from time import time
from argus.engine import State
from argus.callbacks.callback import Callback


class TimerCallback(Callback):
    """Stop training after the specified time.

    Args:
        time_limit (int): Time to run training in seconds.

    """

    def __init__(self, time_limit: int):
        self.time_limit = time_limit
        self.start_time = 0

    def start(self, state: State):
        self.start_time = time()

    def iteration_complete(self, state: State):
        if time() - self.start_time > self.time_limit:
            state.stopped = True
            state.logger.info(f"Run out of time {self.time_limit} sec, "
                              f"{(state.epoch + 1) * (state.iteration + 1)} "
                              f"iterations performed!")

You can find an example of creating custom events here.

Raises

TypeError – Attribute is not callable.

attach(engine: argus.engine.engine.Engine)

Attach callback to the argus.engine.Engine.

Parameters

engine (Engine) – The engine to which the callback will be attached.

Decorator callbacks

argus.callbacks.on_event(event: argus.engine.engine.EventEnum) → Callable

Decorator for creating a callback from a function. The function will be executed when the event is triggered. The function should take argus.engine.State as the first argument.

Parameters

event (EventEnum) – An event that will be associated with the function.

Example

import argus
from argus.engine import Events, State

@argus.callbacks.on_event(Events.START)
def start_callback(state: State):
    state.logger.info("Start training!")

model.fit(train_loader,
          val_loader=val_loader,
          callbacks=[start_callback])

argus.callbacks.on_start(func: Callable) → argus.callbacks.callback.FunctionCallback

Decorator for creating a callback from a function. The function will be executed when the Events.START is triggered. The function should take argus.engine.State as the first argument.

Example

import argus
from argus.engine import State

@argus.callbacks.on_start
def start_callback(state: State):
    state.logger.info("Start training!")

model.fit(train_loader,
          val_loader=val_loader,
          callbacks=[start_callback])

argus.callbacks.on_complete(func: Callable) → argus.callbacks.callback.FunctionCallback

Decorator for creating a callback from a function. The function will be executed when the Events.COMPLETE is triggered. The function should take argus.engine.State as the first argument.

argus.callbacks.on_epoch_start(func: Callable) → argus.callbacks.callback.FunctionCallback

Decorator for creating a callback from a function. The function will be executed when the Events.EPOCH_START is triggered. The function should take argus.engine.State as the first argument.

argus.callbacks.on_epoch_complete(func: Callable) → argus.callbacks.callback.FunctionCallback

Decorator for creating a callback from a function. The function will be executed when the Events.EPOCH_COMPLETE is triggered. The function should take argus.engine.State as the first argument.

argus.callbacks.on_iteration_start(func: Callable) → argus.callbacks.callback.FunctionCallback

Decorator for creating a callback from a function. The function will be executed when the Events.ITERATION_START is triggered. The function should take argus.engine.State as the first argument.

argus.callbacks.on_iteration_complete(func: Callable) → argus.callbacks.callback.FunctionCallback

Decorator for creating a callback from a function. The function will be executed when the Events.ITERATION_COMPLETE is triggered. The function should take argus.engine.State as the first argument.

argus.callbacks.on_catch_exception(func: Callable) → argus.callbacks.callback.FunctionCallback

Decorator for creating a callback from a function. The function will be executed when the Events.CATCH_EXCEPTION is triggered. The function should take argus.engine.State as the first argument.

class argus.callbacks.FunctionCallback(event: argus.engine.engine.EventEnum, handler: Callable)

Callback class for executing a single function.

Parameters

• event (EventEnum) – An event that will be associated with the handler.

• handler (Callable) – A callable handler that will be executed on the event. The handler should take argus.engine.State as the first argument.

attach(engine: argus.engine.engine.Engine, *args, **kwargs)

Attach callback to the argus.engine.Engine.

Parameters

• engine (Engine) – The engine to which the callback will be attached.

• *args – optional args arguments to be passed to the handler.

• **kwargs – optional kwargs arguments to be passed to the handler.

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