Class: DNN::Layers::Embedding

Inherits:
HasParamLayer show all
Defined in:
lib/dnn/core/embedding.rb

Instance Attribute Summary collapse

Attributes inherited from HasParamLayer

#trainable

Attributes inherited from Layer

#input_shape, #name

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Layer

#built?, call, #output_shape

Constructor Details

#initialize(input_dim_or_shape, input_length, weight_initializer: Initializers::RandomUniform.new, weight_regularizer: nil) ⇒ Embedding

Returns a new instance of Embedding.

Parameters:

  • input_dim_or_shape (Integer | Array) —

    Set input data dimension or shape.

  • input_length (Integer) —

    Set the time series length of input data.

  • weight_initializer (DNN::Initializers::Initializer) (defaults to: Initializers::RandomUniform.new) —

    Weight initializer.

  • weight_regularizer (DNN::Regularizers::Regularizer | NilClass) (defaults to: nil) —

    Weight regularizer.



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# File 'lib/dnn/core/embedding.rb', line 20

def initialize(input_dim_or_shape, input_length,
               weight_initializer: Initializers::RandomUniform.new,
               weight_regularizer: nil)
  super()
  @input_shape = input_dim_or_shape.is_a?(Array) ? input_dim_or_shape : [input_dim_or_shape]
  @input_length = input_length
  @weight_initializer = weight_initializer
  @weight_regularizer = weight_regularizer
end

Instance Attribute Details

#input_length ⇒ Object (readonly)

Returns the value of attribute input_length.



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# File 'lib/dnn/core/embedding.rb', line 5

def input_length
  @input_length
end

#weight ⇒ Object (readonly)

Returns the value of attribute weight.



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# File 'lib/dnn/core/embedding.rb', line 6

def weight
  @weight
end

#weight_initializer ⇒ Object (readonly)

Returns the value of attribute weight_initializer.



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# File 'lib/dnn/core/embedding.rb', line 7

def weight_initializer
  @weight_initializer
end

#weight_regularizer ⇒ Object (readonly)

Returns the value of attribute weight_regularizer.



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# File 'lib/dnn/core/embedding.rb', line 8

def weight_regularizer
  @weight_regularizer
end

Class Method Details

.from_hash(hash) ⇒ Object 



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# File 'lib/dnn/core/embedding.rb', line 10

def self.from_hash(hash)
  self.new(hash[:input_shape], hash[:input_length],
           weight_initializer: DNN::Utils.hash_to_obj(hash[:weight_initializer]),
           weight_regularizer: DNN::Utils.hash_to_obj(hash[:weight_regularizer]))
end

Instance Method Details

#backward(dy) ⇒ Object 



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# File 'lib/dnn/core/embedding.rb', line 51

def backward(dy)
  @weight.grad += Xumo::SFloat.zeros(*@weight.data.shape)
  @x.shape[0].times do |i|
    @x.shape[1].times do |j|
      @weight.grad[@x[i, j]] += dy[i, j]
    end
  end
  nil
end

#build ⇒ Object 



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# File 'lib/dnn/core/embedding.rb', line 35

def build
  @built = true
  @weight = Param.new(Xumo::SFloat.new(@input_length), 0)
  @weight_initializer.init_param(self, @weight)
  @weight_regularizer.param = @weight if @weight_regularizer
end

#call(input) ⇒ Object 



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# File 'lib/dnn/core/embedding.rb', line 30

def call(input)
  build unless built?
  [forward(input), Link.new(nil, self)]
end

#forward(x) ⇒ Object 



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# File 'lib/dnn/core/embedding.rb', line 42

def forward(x)
  @x = x
  y = Xumo::SFloat.zeros(*x.shape)
  x.shape[0].times do |i|
    y[i, false] = @weight.data[x[i, false]]
  end
  y
end

#get_params ⇒ Object 



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# File 'lib/dnn/core/embedding.rb', line 70

def get_params
  { weight: @weight }
end

#regularizers ⇒ Object 



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# File 'lib/dnn/core/embedding.rb', line 61

def regularizers
  @weight_regularizer ? [@weight_regularizer] : []
end

#to_hash ⇒ Object 



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# File 'lib/dnn/core/embedding.rb', line 65

def to_hash
  super(input_shape: @input_shape, input_length: @input_length,
        weight_initializer: @weight_initializer.to_hash, weight_regularizer: @weight_regularizer&.to_hash)
end