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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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# http://www.apache.org/licenses/LICENSE-2.0
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""" MonitorTask base classes """
from abc import ABC, abstractmethod
from typing import Any, Callable, Collection, List, Union
import tensorflow as tf
__all__ = ["MonitorTask", "ExecuteCallback", "MonitorTaskGroup", "Monitor"]
[docs]class MonitorTask(ABC):
"""
A base class for a monitoring task.
All monitoring tasks are callable objects.
A descendant class must implement the `run` method, which is the body of the monitoring task.
"""
def __call__(self, step: int, **kwargs: Any) -> None:
"""
It calls the 'run' function and sets the current step.
:param step: current step in the optimisation.
:param kwargs: additional keyword arguments that can be passed
to the `run` method of the task. This is in particular handy for
passing keyword argument to the callback of `ScalarToTensorBoard`.
"""
self.current_step = tf.cast(step, tf.int64)
self.run(**kwargs)
[docs] @abstractmethod
def run(self, **kwargs: Any) -> None:
"""
Implements the task to be executed on __call__.
The current step is available through `self.current_step`.
:param kwargs: keyword arguments available to the run method.
"""
raise NotImplementedError
[docs]class ExecuteCallback(MonitorTask):
""" Executes a callback as task """
def __init__(self, callback: Callable[..., None]) -> None:
"""
:param callback: callable to be executed during the task.
Arguments can be passed using keyword arguments.
"""
super().__init__()
self.callback = callback
[docs] def run(self, **kwargs: Any) -> None:
self.callback(**kwargs)
[docs]class MonitorTaskGroup:
"""
Class for grouping `MonitorTask` instances. A group defines
all the tasks that are run at the same frequency, given by `period`.
A `MonitorTaskGroup` can exist of a single instance or a list of
`MonitorTask` instances.
"""
def __init__(
self, task_or_tasks: Union[Collection[MonitorTask], MonitorTask], period: int = 1
) -> None:
"""
:param task_or_tasks: a single instance or a list of `MonitorTask` instances.
Each `MonitorTask` in the list will be run with the given `period`.
:param period: defines how often to run the tasks; they will execute every `period`th step.
For large values of `period` the tasks will be less frequently run. Defaults to
running at every step (`period = 1`).
"""
self._tasks: Collection[MonitorTask] = []
self.tasks = task_or_tasks # type: ignore
self._period = period
@property
def tasks(self) -> Collection[MonitorTask]:
return self._tasks
@tasks.setter
def tasks(self, task_or_tasks: Union[Collection[MonitorTask], MonitorTask]) -> None:
"""Ensures the tasks are stored as a list. Even if there is only a single task."""
if isinstance(task_or_tasks, MonitorTask):
self._tasks = [task_or_tasks]
else:
assert isinstance(task_or_tasks, Collection)
self._tasks = list(task_or_tasks)
def __call__(self, step: int, **kwargs: Any) -> None:
"""Call each task in the group."""
if step % self._period == 0:
for task in self.tasks:
task(step, **kwargs)
[docs]class Monitor:
r"""
Accepts any number of of `MonitorTaskGroup` instances, and runs them
according to their specified periodicity.
Example use-case:
```
# Create some monitor tasks
log_dir = "logs"
model_task = ModelToTensorBoard(log_dir, model)
image_task = ImageToTensorBoard(log_dir, plot_prediction, "image_samples")
lml_task = ScalarToTensorBoard(log_dir, lambda: model.log_marginal_likelihood(), "lml")
# Plotting tasks can be quite slow, so we want to run them less frequently.
# We group them in a `MonitorTaskGroup` and set the period to 5.
slow_tasks = MonitorTaskGroup(image_task, period=5)
# The other tasks are fast. We run them at each iteration of the optimisation.
fast_tasks = MonitorTaskGroup([model_task, lml_task], period=1)
# We pass both groups to the `Monitor`
monitor = Monitor(fast_tasks, slow_tasks)
```
"""
def __init__(self, *task_groups: MonitorTaskGroup) -> None:
"""
:param task_groups: a list of `MonitorTaskGroup`s to be executed.
"""
self.task_groups = task_groups
def __call__(self, step: int, **kwargs: Any) -> None:
for group in self.task_groups:
group(step, **kwargs)