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Pull Request — master (#202)
by Grega
01:02
created

HillClimbAlgorithm.runIteration()   A

Complexity

Conditions 3

Size

Total Lines 24
Code Lines 8

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 3
eloc 8
nop 7
dl 0
loc 24
rs 10
c 0
b 0
f 0
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# encoding=utf8
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# pylint: disable=mixed-indentation, trailing-whitespace, multiple-statements, attribute-defined-outside-init, logging-not-lazy, arguments-differ, redefined-outer-name, bad-continuation, unused-argument
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import logging
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from numpy import random as rand
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from NiaPy.algorithms.algorithm import Algorithm
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logging.basicConfig()
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logger = logging.getLogger('NiaPy.algorithms.other')
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logger.setLevel('INFO')
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__all__ = ['HillClimbAlgorithm']
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def Neighborhood(x, delta, task, rnd=rand):
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	r"""Get neighbours of point.
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	Args:
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		x numpy.ndarray: Point.
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		delta (float): Standard deviation.
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		task (Task): Optimization task.
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		rnd (Optional[mtrand.RandomState]): Random generator.
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	Returns:
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		Tuple[numpy.ndarray, float]:
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			1. New solution.
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			2. New solutions function/fitness value.
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	"""
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	X = x + rnd.normal(0, delta, task.D)
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	X = task.repair(X, rnd)
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	Xfit = task.eval(X)
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	return X, Xfit
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class HillClimbAlgorithm(Algorithm):
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	r"""Implementation of iterative hill climbing algorithm.
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	Algorithm:
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		Hill Climbing Algorithm
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	Date:
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		2018
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	Authors:
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		Jan Popič
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	License:
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		MIT
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	Reference URL:
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	Reference paper:
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	See Also:
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		* :class:`NiaPy.algorithms.Algorithm`
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	Attributes:
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		delta (float): Change for searching in neighborhood.
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		Neighborhood (Callable[numpy.ndarray, float, Task], Tuple[numpy.ndarray, float]]): Function for getting neighbours.
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	"""
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	Name = ['HillClimbAlgorithm', 'BBFA']
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	@staticmethod
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	def algorithmInfo():
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		r"""Get basic information of algorithm.
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		Returns:
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			str: Basic information.
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		"""
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		return r"""TODO"""
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	@staticmethod
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	def typeParameters():
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		r"""TODO.
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		Returns:
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			Dict[str, Callable]:
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				* delta (Callable[[Union[int, float]], bool]): TODO
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		"""
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		return {'delta': lambda x: isinstance(x, (int, float)) and x > 0}
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	def setParameters(self, delta=0.5, Neighborhood=Neighborhood, **ukwargs):
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		r"""Set the algorithm parameters/arguments.
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		Args:
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			* delta (Optional[float]): Change for searching in neighborhood.
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			* Neighborhood (Optional[Callable[numpy.ndarray, float, Task], Tuple[numpy.ndarray, float]]]): Function for getting neighbours.
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		"""
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		Algorithm.setParameters(self, NP=1, **ukwargs)
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		self.delta, self.Neighborhood = delta, Neighborhood
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		if ukwargs: logger.info('Unused arguments: %s' % (ukwargs))
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	def initPopulation(self, task):
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		r"""Initialize stating point.
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		Args:
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			task (Task): Optimization task.
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		Returns:
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			Tuple[numpy.ndarray, float, Dict[str, Any]]:
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				1. New individual.
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				2. New individual function/fitness value.
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				3. Additional arguments.
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		"""
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		x = task.Lower + self.rand(task.D) * task.bRange
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		return x, task.eval(x), {}
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	def runIteration(self, task, x, fx, xb, fxb, **dparams):
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		r"""Core function of HillClimbAlgorithm algorithm.
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		Args:
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			task (Task): Optimization task.
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			x (numpy.ndarray): Current solution.
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			fx (float): Current solutions fitness/function value.
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			xb (numpy.ndarray): Global best solution.
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			fxb (float): Global best solutions function/fitness value.
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			**dparams (Dict[str, Any]): Additional arguments.
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		Returns:
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			Tuple[numpy.ndarray, float, Dict[str, Any]]:
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				1. New solution.
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				2. New solutions function/fitness value.
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				3. Additional arguments.
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		"""
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		lo, xn = False, task.bcLower() + task.bcRange() * self.rand(task.D)
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		xn_f = task.eval(xn)
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		while not lo:
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			yn, yn_f = self.Neighborhood(x, self.delta, task, rnd=self.Rand)
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			if yn_f < xn_f: xn, xn_f = yn, yn_f
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			else: lo = True or task.stopCond()
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		return xn, xn_f, {}
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# vim: tabstop=3 noexpandtab shiftwidth=3 softtabstop=3
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