Class: Population

Inherits:
Object
  • Object
show all
Defined in:
lib/gimuby/genetic/population/population.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(solutions = nil) ⇒ Population

Returns a new instance of Population.



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# File 'lib/gimuby/genetic/population/population.rb', line 7

def initialize(solutions = nil)
  if solutions.nil?
    @solutions = []
  else
    @solutions = solutions
  end
  @pick_strategy ||= RandomWheelPickStrategy.new
  @replace_strategy ||= ReplaceWorstReplaceStrategy.new

  trigger(:on_population_init)
end

Instance Attribute Details

#pick_strategy ⇒ Object

Returns the value of attribute pick_strategy.



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# File 'lib/gimuby/genetic/population/population.rb', line 20

def pick_strategy
  @pick_strategy
end

#replace_strategy ⇒ Object

Returns the value of attribute replace_strategy.



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# File 'lib/gimuby/genetic/population/population.rb', line 22

def replace_strategy
  @replace_strategy
end

#selection_rate ⇒ Object

Returns the value of attribute selection_rate.



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# File 'lib/gimuby/genetic/population/population.rb', line 21

def selection_rate
  @selection_rate
end

#solutions ⇒ Object (readonly)

Returns the value of attribute solutions.



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# File 'lib/gimuby/genetic/population/population.rb', line 19

def solutions
  @solutions
end

Instance Method Details

#add_solution(solution) ⇒ Object

Add a solution

Parameters:



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# File 'lib/gimuby/genetic/population/population.rb', line 53

def add_solution(solution)
  @solutions.push solution
end

#generation_step ⇒ Object

Run a step of genetic algorithm: reproduction + mutation



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# File 'lib/gimuby/genetic/population/population.rb', line 25

def generation_step
  reproduce
  @solutions.each do |solution|
    solution.mutate
  end
  trigger(:on_population_generation_step)
end

#get_average_fitness ⇒ Object 



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# File 'lib/gimuby/genetic/population/population.rb', line 66

def get_average_fitness
  sum = 0
  @solutions.each do |solution|
    sum += solution.get_fitness
  end
  # Beware of that division by 0
  sum / @solutions.length
end

#get_best_fitness ⇒ Object 



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# File 'lib/gimuby/genetic/population/population.rb', line 75

def get_best_fitness
  best_solution = get_best_solution
  best_solution.get_fitness
end

#get_best_solution ⇒ Object 



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# File 'lib/gimuby/genetic/population/population.rb', line 80

def get_best_solution
  best_solution = @solutions.min_by do |solution|
    solution.get_fitness
  end
  best_solution
end

#get_fitness(solution) ⇒ Object

Can be overridden



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# File 'lib/gimuby/genetic/population/population.rb', line 62

def get_fitness(solution)
  solution.get_fitness
end

#get_population_size ⇒ Object 



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# File 'lib/gimuby/genetic/population/population.rb', line 57

def get_population_size
  @solutions.size
end

#pick ⇒ Object

Pick some solutions



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# File 'lib/gimuby/genetic/population/population.rb', line 47

def pick
  @pick_strategy.pick(self)
end

#replace(solutions) ⇒ Object

Replace part of the population (used by Archipelago)



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# File 'lib/gimuby/genetic/population/population.rb', line 35

def replace(solutions)
  @solutions = @replace_strategy.replace(self, solutions)
end

#reproduce ⇒ Object

Simply pick some solutions and make them reproduce



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# File 'lib/gimuby/genetic/population/population.rb', line 41

def reproduce
  @solutions = @replace_strategy.replace(self)
end