Class: DNN::Layers::LSTM

Inherits:
RNN show all
Defined in:
lib/dnn/core/rnn_layers.rb

Instance Attribute Summary collapse

Attributes inherited from RNN

#h, #num_nodes, #stateful, #weight_decay

Attributes inherited from HasParamLayer

#grads, #params, #trainable

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from RNN

#ridge, #shape, #to_hash

Methods inherited from HasParamLayer

#build, #update

Methods inherited from Layer

#build, #built?, #prev_layer, #shape, #to_hash

Constructor Details

#initialize(num_nodes, stateful: false, return_sequences: true, weight_initializer: nil, bias_initializer: nil, weight_decay: 0) ⇒ LSTM

Returns a new instance of LSTM.



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# File 'lib/dnn/core/rnn_layers.rb', line 233

def initialize(num_nodes,
               stateful: false,
               return_sequences: true,
               weight_initializer: nil,
               bias_initializer: nil,
               weight_decay: 0)
  super
  @cell = nil
end

Instance Attribute Details

#cell ⇒ Object

Returns the value of attribute cell.



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# File 'lib/dnn/core/rnn_layers.rb', line 222

def cell
  @cell
end

Class Method Details

.load_hash(hash) ⇒ Object 



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# File 'lib/dnn/core/rnn_layers.rb', line 224

def self.load_hash(hash)
  self.new(hash[:num_nodes],
           stateful: hash[:stateful],
           return_sequences: hash[:return_sequences],
           weight_initializer: Util.load_hash(hash[:weight_initializer]),
           bias_initializer: Util.load_hash(hash[:bias_initializer]),
           weight_decay: hash[:weight_decay])
end

Instance Method Details

#backward(dh2s) ⇒ Object 



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# File 'lib/dnn/core/rnn_layers.rb', line 264

def backward(dh2s)
  @grads[:weight] = Xumo::SFloat.zeros(*@params[:weight].shape)
  @grads[:weight2] = Xumo::SFloat.zeros(*@params[:weight2].shape)
  @grads[:bias] = Xumo::SFloat.zeros(*@params[:bias].shape)
  unless @return_sequences
    dh = dh2s
    dh2s = Xumo::SFloat.zeros(dh.shape[0], @time_length, dh.shape[1])
    dh2s[true, -1, false] = dh
  end
  dxs = Xumo::SFloat.zeros(@xs_shape)
  dh = 0
  dcell = 0
  (0...dh2s.shape[1]).to_a.reverse.each do |t|
    dh2 = dh2s[true, t, false]
    dx, dh, dcell = @layers[t].backward(dh2 + dh, dcell)
    dxs[true, t, false] = dx
  end
  dxs
end

#forward(xs) ⇒ Object 



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# File 'lib/dnn/core/rnn_layers.rb', line 243

def forward(xs)
  @xs_shape = xs.shape
  hs = Xumo::SFloat.zeros(xs.shape[0], @time_length, @num_nodes)
  h = nil
  cell = nil
  if @stateful
    h = @h if @h
    cell = @cell if @cell
  end
  h ||= Xumo::SFloat.zeros(xs.shape[0], @num_nodes)
  cell ||= Xumo::SFloat.zeros(xs.shape[0], @num_nodes)
  xs.shape[1].times do |t|
    x = xs[true, t, false]
    h, cell = @layers[t].forward(x, h, cell)
    hs[true, t, false] = h
  end
  @h = h
  @cell = cell
  @return_sequences ? hs : h
end