Class: DNN::Layers::MaxPool2D

Inherits:
Pool2D show all
Includes:
LayerNode
Defined in:
lib/dnn/core/layers/cnn_layers.rb

Instance Attribute Summary

Attributes inherited from Pool2D

#padding, #pool_size, #strides

Attributes inherited from Layer

#input_shape, #output_shape

Instance Method Summary collapse

Methods included from LayerNode

#forward

Methods inherited from Pool2D

#build, #compute_output_shape, #initialize, #load_hash, #to_hash

Methods included from Conv2DUtils

calc_conv2d_out_size, calc_conv2d_padding_size, calc_conv2d_transpose_out_size, calc_conv2d_transpose_padding_size, col2im, col2im_cpu, col2im_gpu, im2col, im2col_cpu, im2col_gpu, zero_padding, zero_padding_bwd

Methods inherited from Layer

#<<, #build, #built?, #call, call, #clean, #compute_output_shape, #forward, from_hash, #initialize, #load_hash, #to_hash

Constructor Details

This class inherits a constructor from DNN::Layers::Pool2D

Instance Method Details

#backward_node(dy) ⇒ Object 



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# File 'lib/dnn/core/layers/cnn_layers.rb', line 389

def backward_node(dy)
  dmax = Xumo::SFloat.zeros(dy.size * @pool_size.reduce(:*))
  dmax[@max_index.flatten] = dy.flatten
  dcol = dmax.reshape(dy.shape[0..2].reduce(:*), @pool_size.reduce(:*) * dy.shape[3])
  dx = col2im(dcol, @x_shape, *@out_size, *@pool_size, @strides)
  @padding ? zero_padding_bwd(dx, @pad_size) : dx
end

#forward_node(x) ⇒ Object 



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# File 'lib/dnn/core/layers/cnn_layers.rb', line 380

def forward_node(x)
  x = zero_padding(x, @pad_size) if @padding
  @x_shape = x.shape
  col = im2col(x, *@out_size, *@pool_size, @strides)
  col = col.reshape(x.shape[0] * @out_size.reduce(:*), @pool_size.reduce(:*), x.shape[3])
  @max_index = col.max_index(1)
  col.max(1).reshape(x.shape[0], *@out_size, x.shape[3])
end