Class: SA::Context

Inherits:
Object
  • Object
show all
Defined in:
lib/sa/context.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#best_energy ⇒ Object

Returns the value of attribute best_energy.



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# File 'lib/sa/context.rb', line 3

def best_energy
  @best_energy
end

#best_state ⇒ Object

Returns the value of attribute best_state.



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# File 'lib/sa/context.rb', line 3

def best_state
  @best_state
end

Instance Method Details

#annealing(unit, temp, stop_temp, cool_proc) ⇒ Object

options:

temp: Int or Float
cool: Proc, return new Temp
stop_temp: Int or Float, stop annealing when temp < stop_temp



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# File 'lib/sa/context.rb', line 9

def annealing(unit, temp, stop_temp, cool_proc)
  @best_state = unit.state
  @best_energy = unit.energy

  @current_energy = unit.energy
  @current_temp = temp.to_f

  while @current_temp > stop_temp do
    unit.sa_iteration(self, @current_temp)
    @current_temp = cool_proc.call(@current_temp).to_f
  end

  unit.state = @best_state if @best_energy < unit.energy
  unit
end

#transfer(energy, state) ⇒ Object 



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# File 'lib/sa/context.rb', line 25

def transfer(energy, state)
  if energy <= @current_energy
    @current_energy = energy
    if energy < best_energy
      @best_energy = energy
      @best_state = state.dup
    end
    true
  else
    p = Math::E ** -((energy - @current_energy) / @current_temp)
    v = Kernel.rand
    if v < p
      @current_energy = energy
      true
    else
      false
    end
  end
end