optuna.integration.fastaiv1 源代码

from typing import Any

from packaging import version

import optuna
from optuna._deprecated import deprecated
from optuna._imports import try_import

with try_import() as _imports:
    import fastai

    if version.parse(fastai.__version__) >= version.parse("2.0.0"):
        raise ImportError(
            f"You don't have fastai V1 installed! Fastai version: {fastai.__version__}"

    from fastai.basic_train import Learner
    from fastai.callbacks import TrackerCallback

if not _imports.is_successful():
    TrackerCallback = object  # NOQA

[文档]@deprecated("2.4.0") class FastAIV1PruningCallback(TrackerCallback): """FastAI callback to prune unpromising trials for fastai. .. note:: This callback is for fastai<2.0. See `the example <https://github.com/optuna/optuna/blob/master/ examples/fastai/fastaiv1_simple.py>`__ if you want to add a pruning callback which monitors validation loss of a ``Learner``. Example: Register a pruning callback to ``learn.fit`` and ``learn.fit_one_cycle``. .. code:: learn.fit(n_epochs, callbacks=[FastAIPruningCallback(learn, trial, "valid_loss")]) learn.fit_one_cycle( n_epochs, cyc_len, max_lr, callbacks=[FastAIPruningCallback(learn, trial, "valid_loss")], ) Args: learn: `fastai.basic_train.Learner <https://docs.fast.ai/basic_train.html#Learner>`_. trial: A :class:`~optuna.trial.Trial` corresponding to the current evaluation of the objective function. monitor: An evaluation metric for pruning, e.g. ``valid_loss`` and ``Accuracy``. Please refer to `fastai.callbacks.TrackerCallback reference <https://fastai1.fast.ai/callbacks.tracker.html#TrackerCallback>`_ for further details. """ def __init__(self, learn: "Learner", trial: optuna.trial.Trial, monitor: str) -> None: super().__init__(learn, monitor) _imports.check() self._trial = trial def on_epoch_end(self, epoch: int, **kwargs: Any) -> None: value = self.get_monitor_value() if value is None: return # This conversion is necessary to avoid problems reported in issues. # - https://github.com/optuna/optuna/issue/642 # - https://github.com/optuna/optuna/issue/655. self._trial.report(float(value), step=epoch) if self._trial.should_prune(): message = "Trial was pruned at epoch {}.".format(epoch) raise optuna.TrialPruned(message)