Class: Wallace::Operators::SubtourExchangeCrossoverOperator
- Inherits:
-
Wallace::Operator
- Object
- Wallace::Operator
- Wallace::Operators::SubtourExchangeCrossoverOperator
- Defined in:
- lib/operators/subtour_exchange_crossover_operation.rb
Overview
INCREDIBLY SLOW! O(n^3)
Defined Under Namespace
Classes: Subtour
Instance Method Summary collapse
Methods inherited from Wallace::Operator
Constructor Details
This class inherits a constructor from Wallace::Operator
Instance Method Details
#operate(rng, inputs) ⇒ Object
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# File 'lib/operators/subtour_exchange_crossover_operation.rb', line 11 def operate(rng, inputs) # Calculate the set of all subtours within each parent # chromosome that are greater than length 1 and shorter # than the entire tour length. len = inputs[0].length subtours = (0..1).map do |input| Hash[(2...len).map { |k| [k, (0...len).cons(k).map { |bounds| bounds = bounds.first..bounds.last Subtour.new(inputs[input][bounds], bounds) }] }] end # Check each k-length subtour for the same vertices. subtours = Hash[(2...len).map { |k| [ k, subtours[0][k].product(subtours[1][k]).select { |s1, s2| s1.tour - s2.tour == s2.tour - s1.tour }] }] # Reduce the set of sub-tours to a non-overlapping set. # (i.e. there are no (k-1)-length tours contained within a k-length tour). # # Alternatively we could perform replacements in ascending order # of subtour length. Simpler and gives the same result, but more replacements # are performed; is there much of a performance gain from pre-processing the # set of candidate subtours? # # For now we will stick to the latter for the sake of simplicity. subtours.each_value do |k_subtours| k_subtours.each do |s1, s2| inputs[0][s1.bounds] = s2.tour inputs[1][s2.bounds] = s1.tour end end return inputs end |