Class: EvoSynth::Evolvers::LocalSearch::RecordToRecordTravelAcceptance

Inherits:
Object
  • Object
show all
Defined in:
lib/evosynth/evolvers/local_search/acceptance_record_to_record.rb

Overview

AKZEPTANZ-RR (Weicker Page 158)

Constant Summary collapse

DEFAULT_START_DELTA = 
Float::MAX
DEFAULT_ALPHA = 
0.9

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(start_delta = DEFAULT_START_DELTA, alpha = DEFAULT_ALPHA) ⇒ RecordToRecordTravelAcceptance

Returns a new instance of RecordToRecordTravelAcceptance.

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# File 'lib/evosynth/evolvers/local_search/acceptance_record_to_record.rb', line 38

def initialize(start_delta = DEFAULT_START_DELTA, alpha = DEFAULT_ALPHA)
	@delta = start_delta
	@alpha = alpha
	@best = nil
end

Instance Attribute Details

#alpha ⇒ Object

Returns the value of attribute alpha.


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# File 'lib/evosynth/evolvers/local_search/acceptance_record_to_record.rb', line 33

def alpha
  @alpha
end

#delta ⇒ Object

Returns the value of attribute delta.


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# File 'lib/evosynth/evolvers/local_search/acceptance_record_to_record.rb', line 33

def delta
  @delta
end

Instance Method Details

#accepts(parent, child, generation) ⇒ Object

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# File 'lib/evosynth/evolvers/local_search/acceptance_record_to_record.rb', line 44

def accepts(parent, child, generation)
	@best = parent if @best.nil?
	accepted = false

	if child > @best
		@best = child
		accepted = true
	else
		threshold = Math.sqrt( (child.fitness - @best.fitness)**2 )
		accepted = threshold < @delta
	end

	@delta *= @alpha
	accepted
end

#to_s ⇒ Object

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# File 'lib/evosynth/evolvers/local_search/acceptance_record_to_record.rb', line 60

def to_s
	"Record-to-Record-Travel Acceptance"
end