58 lines
1.4 KiB
Ruby
58 lines
1.4 KiB
Ruby
# Copyright (C) 2024 Manuel Bustillo
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module VNS
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class Engine
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class << self
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def sequence(elements)
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elements = elements.to_a
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(elements + elements.reverse).chunk(&:itself).map(&:first)
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end
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end
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def target_function(&function)
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@target_function = function
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end
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def add_perturbation(klass)
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@perturbations ||= Set.new
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@perturbations << klass
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end
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attr_writer :initial_solution
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def run
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raise 'No target function defined' unless @target_function
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raise 'No perturbations defined' unless @perturbations
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raise 'No initial solution defined' unless @initial_solution
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@best_solution = @initial_solution
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@best_score = @target_function.call(@best_solution)
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puts "Initial score: #{@best_score.to_f}"
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self.class.sequence(@perturbations).each do |perturbation|
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puts "Running perturbation: #{perturbation.name}"
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optimize(perturbation.new(@best_solution))
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end
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@best_solution
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end
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private
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def optimize(perturbation)
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perturbation.each do |alternative_solution|
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score = @target_function.call(alternative_solution)
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next if score >= @best_score
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@best_solution = alternative_solution.deep_dup
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@best_score = score
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puts "New lowest score: #{@best_score.to_f}"
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return optimize(perturbation.class.new(@best_solution))
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end
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end
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end
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end
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