Class: Ai4r::Som::TwoPhaseLayer

Inherits:
Layer
  • Object
show all
Defined in:
lib/ai4r/som/two_phase_layer.rb

Overview

Layer that trains in two distinct phases with different learning rates.

Instance Method Summary collapse

Methods inherited from Layer

#influence_decay

Methods included from Data::Parameterizable

#get_parameters, included, #set_parameters

Constructor Details

#initialize(nodes, learning_rate = 0.9, phase_one = 150, phase_two = 100, phase_one_learning_rate = 0.1, phase_two_learning_rate = 0, options = {}) ⇒ Object 



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# File 'lib/ai4r/som/two_phase_layer.rb', line 37

def initialize(nodes, learning_rate = 0.9, phase_one = 150, phase_two = 100,
               phase_one_learning_rate = 0.1, phase_two_learning_rate = 0, options = {})
  super(nodes, nodes, phase_one + phase_two, learning_rate, options)
  @phase_one = phase_one
  @phase_two = phase_two
  @lr = @initial_learning_rate

  @phase_one_learning_rate = phase_one_learning_rate
  @phase_two_learning_rate = phase_two_learning_rate

  @radius_reduction = (@phase_one / ((nodes / 2.0) - 1)) + 1
  @delta_lr = (@lr - @phase_one_learning_rate) / @phase_one
  @radius = (nodes / 2.0).to_i
end

Instance Method Details

#learning_rate_decay(epoch) ⇒ Object

two different values will be returned, depending on the phase in phase one, the rate will incrementially reduced everytime this method is called on the switch of phases, the learning rate will be reset and the delta_lr (which signals the decay value of the learning rate) is reset as well in phase two, the newly reset delta_lr rate will be used to incrementially reduce the learning rate

Parameters:

  • epoch (Object)

Returns:

  • (Object) 


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# File 'lib/ai4r/som/two_phase_layer.rb', line 72

def learning_rate_decay(epoch)
  if epoch < @phase_one
    @lr -= @delta_lr
    @lr
  elsif epoch == @phase_one
    @lr = @phase_one_learning_rate
    @delta_lr = (@phase_one_learning_rate - @phase_two_learning_rate) / @phase_two
    @lr
  else
    @lr -= @delta_lr
  end
end

#radius_decay(epoch) ⇒ Object

two different values will be returned, depending on the phase in phase one, the radius will incrementially reduced by 1 every @radius_reduction time in phase two, the radius is fixed to 1

Parameters:

  • epoch (Object)

Returns:

  • (Object) 


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# File 'lib/ai4r/som/two_phase_layer.rb', line 57

def radius_decay(epoch)
  return 1 if epoch > @phase_one

  @radius -= 1 if (epoch % @radius_reduction).zero?
  @radius
end