Source code for composer.callbacks.threshold_stopper

# Copyright 2022 MosaicML Composer authors
# SPDX-License-Identifier: Apache-2.0

"""Threshold stopping callback."""

from typing import Any, Callable, Optional, Union

import torch

from composer.core import Callback, State
from composer.loggers import Logger


[docs]class ThresholdStopper(Callback): """Halt training when a metric value reaches a certain threshold. Example: .. doctest:: >>> from composer import Evaluator, Trainer >>> from composer.callbacks.threshold_stopper import ThresholdStopper >>> # constructing trainer object with this callback >>> threshold_stopper = ThresholdStopper('MulticlassAccuracy', 'my_evaluator', 0.7) >>> evaluator = Evaluator( ... dataloader = eval_dataloader, ... label = 'my_evaluator', ... metric_names = ['MulticlassAccuracy'] ... ) >>> trainer = Trainer( ... model=model, ... train_dataloader=train_dataloader, ... eval_dataloader=evaluator, ... optimizers=optimizer, ... max_duration="1ep", ... callbacks=[threshold_stopper], ... ) Args: monitor (str): The name of the metric to monitor. dataloader_label (str): The label of the dataloader or evaluator associated with the tracked metric. If monitor is in an Evaluator, the dataloader_label field should be set to the Evaluator's label. If monitor is a training metric or an ordinary evaluation metric not in an Evaluator, dataloader_label should be set to 'train' or 'eval' respectively. If dataloader_label is set to 'train', then the callback will stop training in the middle of the epoch. threshold (float): The threshold that dictates when to halt training. Whether training stops if the metric exceeds or falls below the threshold depends on the comparison operator. comp (Callable[[Any, Any], Any], optional): A comparison operator to measure change of the monitored metric. The comparison operator will be called ``comp(current_value, prev_best)``. For metrics where the optimal value is low (error, loss, perplexity), use a less than operator and for metrics like accuracy where the optimal value is higher, use a greater than operator. Defaults to :func:`torch.less` if loss, error, or perplexity are substrings of the monitored metric, otherwise defaults to :func:`torch.greater` stop_on_batch (bool, optional): A bool that indicates whether to stop training in the middle of an epoch if the training metrics satisfy the threshold comparison. Defaults to False. """ def __init__(self, monitor: str, dataloader_label: str, threshold: float, *, comp: Optional[Union[str, Callable[[ Any, Any, ], Any]]] = None, stop_on_batch: bool = False): self.monitor = monitor self.threshold = threshold self.dataloader_label = dataloader_label self.stop_on_batch = stop_on_batch if callable(comp): self.comp_func = comp if isinstance(comp, str): if comp.lower() in ('greater', 'gt'): self.comp_func = torch.greater elif comp.lower() in ('less', 'lt'): self.comp_func = torch.less else: raise ValueError( "Unrecognized comp string. Use the strings 'gt', 'greater', 'lt' or 'less' or a callable comparison operator" ) if comp is None: if any(substr in monitor.lower() for substr in ['loss', 'error', 'perplexity']): self.comp_func = torch.less else: self.comp_func = torch.greater def _get_monitored_metric(self, state: State): if self.dataloader_label == 'train' and state.train_metrics is not None: if self.monitor in state.train_metrics: return state.train_metrics[self.monitor].compute() else: if self.monitor in state.eval_metrics[self.dataloader_label]: return state.eval_metrics[self.dataloader_label][self.monitor].compute() raise ValueError(f"Couldn't find the metric {self.monitor} with the dataloader label {self.dataloader_label}." "Check that the dataloader_label is set to 'eval', 'train' or the evaluator name.") def _compare_metric_and_update_state(self, state: State): metric_val = self._get_monitored_metric(state) if not torch.is_tensor(metric_val): metric_val = torch.tensor(metric_val) if self.comp_func(metric_val, self.threshold): state.stop_training() def eval_end(self, state: State, logger: Logger) -> None: if self.dataloader_label == state.dataloader_label: # if the monitored metric is an eval metric or in an evaluator self._compare_metric_and_update_state(state) def epoch_end(self, state: State, logger: Logger) -> None: if self.dataloader_label == state.dataloader_label: # if the monitored metric is not an eval metric, the right logic is run on EPOCH_END self._compare_metric_and_update_state(state) def batch_end(self, state: State, logger: Logger) -> None: if self.stop_on_batch and self.dataloader_label == state.dataloader_label: self._compare_metric_and_update_state(state)