Class: Stochastic::RandomSearch

Inherits:
Object
  • Object
show all
Defined in:
lib/Algorithmically/Stochastic/random_search.rb

Instance Method Summary collapse

Constructor Details

#initialize(size, max_iter) ⇒ RandomSearch

Returns a new instance of RandomSearch.



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# File 'lib/Algorithmically/Stochastic/random_search.rb', line 5

def initialize(size, max_iter)
  problem_size = size
  search_space = Array.new(problem_size) { |i| [-5, +5] }
  maximum_iterations = max_iter
  best_solution = self.search(search_space, maximum_iterations)
  puts "Done. Best Solution: c = #{best_solution[:cost]}, v = #{best_solution[:vector].inspect}"
end

Instance Method Details

#objective_function(vector) ⇒ Object 



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# File 'lib/Algorithmically/Stochastic/random_search.rb', line 13

def objective_function(vector)
  vector.inject(0) { |sum, x| sum + (x ** 2.0) }
end

#random_vector(minmax) ⇒ Object 



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# File 'lib/Algorithmically/Stochastic/random_search.rb', line 17

def random_vector(minmax)
  Array.new(minmax.size) do |i|
    minmax[i][0] + ((minmax[i][1]) - minmax[i][0] * rand())
  end
end

#search(search_space, maximum_iterations) ⇒ Object 



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# File 'lib/Algorithmically/Stochastic/random_search.rb', line 23

def search(search_space, maximum_iterations)
  best_solution = nil
  maximum_iterations.times do |iterate|
    search_candidate = {}
    search_candidate[:vector] = random_vector(search_space)
    search_candidate[:cost] = objective_function(search_candidate[:vector])
    best_solution = search_candidate if best_solution.nil? or search_candidate[:cost] < best_solution[:cost]
    puts " > iteration = #{(iterate + 1)}, best = #{best_solution[:cost]}"
  end
  best_solution
end