"""
.. currentmodule:: mlpy.planners.explorers
Explorers
=========
.. autosummary::
:toctree: generated/
:nosignatures:
ExplorerFactory
IExplorer
Discrete explorers
------------------
.. autosummary::
:toctree: generated/
:nosignatures:
~discrete.DiscreteExplorer
~discrete.EGreedyExplorer
~discrete.SoftmaxExplorer
"""
from __future__ import division, print_function, absolute_import
from ...modules.patterns import RegistryInterface
[docs]class ExplorerFactory(object):
"""The explorer factory.
An instance of an explorer can be created by passing the explorer type.
Examples
--------
>>> from mlpy.planners.explorers import ExplorerFactory
>>> ExplorerFactory.create('egreedyexplorer', 0.8)
This creates a :class:.EGreedyExplorer` instance with epsilon set
to 0.8.
>>> ExplorerFactory.create('softmaxexplorer', tau=3.0, decay=0.4)
This creates a :class:`.SoftmaxExplorer` instance with tau set to
3.0 and decay set to 0.4
"""
@staticmethod
[docs] def create(_type, *args, **kwargs):
"""
Create an explorer of the given type .
Parameters
----------
_type : str
The explorer type. Valid explorer types:
egreedyexplorer
With :math:`\\epsilon` probability, a random action is
chosen, otherwise the action resulting in the highest
q-value is selected. An :class:`.EGreedyExplorer` is created.
softmaxexplorer
The softmax explorer varies the action probability as a
graded function of estimated value. The greedy action is
still given the highest selection probability, but all the others
are ranked and weighted according to their value estimates.
A :class:`.SoftmaxExplorer` is created.
args : tuple
Positional arguments passed to the class of the given type for
initialization.
kwargs : dict
Non-positional arguments passed to the class of the given type
for initialization.
Returns
-------
IExplorer :
An explorer instance of the given type.
"""
# noinspection PyUnresolvedReferences
return IExplorer.registry[_type.lower()](*args, **kwargs)
[docs]class IExplorer(object):
"""The explorer interface class.
The explorer class executes the exploration policy.
Notes
-----
All explorers should derive from this class.
"""
__metaclass__ = RegistryInterface
def __init__(self):
self._is_active = True
def __getstate__(self):
return self.__dict__.copy()
def __setstate__(self, d):
for name, value in d.iteritems():
setattr(self, name, value)
[docs] def activate(self):
"""Turn on exploration mode."""
self._is_active = True
[docs] def deactivate(self):
"""Turn off exploration mode."""
self._is_active = False
[docs] def choose_action(self, *args, **kwargs):
"""Choose the next action according to the exploration strategy.
Parameters
----------
args : tuple
Positional arguments.
kwargs : dict
Non-positional arguments.
Returns
-------
Action :
The next action to taken.
Raises
------
NotImplementedError:
If the child class does not implement this function.
"""
return NotImplementedError
from .discrete import *
__all__ = [s for s in dir() if not (s.startswith('_') or s.endswith('cython'))]