Manuel Bustillo 8c4e6a0109
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Initial version of VNS algorithm (#8)
Reviewed-on: #8
Co-authored-by: Manuel Bustillo <bustikiller@bustikiller.com>
Co-committed-by: Manuel Bustillo <bustikiller@bustikiller.com>
2024-08-01 18:27:41 +00:00

49 lines
1.2 KiB
Ruby

module VNS
class Engine
def target_function(&function)
@target_function = function
end
def add_perturbation(klass)
@perturbations ||= Set.new
@perturbations << klass
end
attr_writer :initial_solution
def run
raise 'No target function defined' unless @target_function
raise 'No perturbations defined' unless @perturbations
raise 'No initial solution defined' unless @initial_solution
@best_solution = @initial_solution
@best_score = @target_function.call(@best_solution)
puts "Initial score: #{@best_score.to_f}"
@perturbations.each do |perturbation|
puts "Running perturbation: #{perturbation.name}"
optimize(perturbation.new(@best_solution))
end
@best_solution
end
private
def optimize(perturbation)
perturbation.each do |alternative_solution|
score = @target_function.call(alternative_solution)
next if score >= @best_score
@best_solution = alternative_solution.deep_dup
@best_score = score
puts "New lowest score: #{@best_score.to_f}"
return optimize(perturbation.class.new(@best_solution))
end
end
end
end