Module: Chainer::Dataset::Convert

Defined in:
lib/chainer/dataset/convert.rb

Class Method Summary collapse

Class Method Details

._concat_arrays(arrays, padding, device) ⇒ Object 



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# File 'lib/chainer/dataset/convert.rb', line 31

def self._concat_arrays(arrays, padding, device)
  xm = device.xm
  unless arrays[0].kind_of?(xm::NArray)
    # [1, 2, 3, 4] => Numo::Int32[1, 2, 3, 4]
    arrays = xm::NArray.cast(arrays)
    if padding
      return _concat_arrays_with_padding(arrays, padding, device)
    end
    return arrays
  end

  if padding
    return _concat_arrays_with_padding(arrays, padding, device)
  end

  # [Numo::SFloat[1, 2], Numo::SFloat[3, 4]]
  #  => Numo::SFloat#shape=[2,2]
  # [[1, 2], [3, 4]]
  a = arrays.map{|arr| arr[:-, false]}
  a[0].concatenate(*a[1..-1])
end

._concat_arrays_with_padding(arrays, padding, device) ⇒ Object 



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# File 'lib/chainer/dataset/convert.rb', line 53

def self._concat_arrays_with_padding(arrays, padding, device)
  xm = device.xm
  if Chainer.array?(arrays[0]) and arrays[0].ndim > 0
    xm = Chainer.get_array_module(arrays[0])
    shape = xm::Int32.cast(arrays[0].shape)
    arrays[1..-1].each do |array|
      if xm::Bit.[](shape != array.shape).any?
        shape = xm::Int32.maximum(shape, array.shape)
      end
    end
  else # Integer
    shape = []
  end

  shape = shape.insert(0, arrays.size).to_a
  if Chainer.array?(arrays[0]) and arrays[0].ndim > 0
    result = arrays[0].class.new(shape).fill(padding)
  else # Integer
    result = xm::Int32.new(shape).fill(padding)
  end

  arrays.size.times do |i|
    src = arrays[i]
    if Chainer.array?(src) and src.ndim > 0
      result[i, 0...src.shape[0], 0...src.shape[1]] = src
    else # Integer
      result[i] = src
    end
  end

  result
end

.concat_examples(batch, device: nil, padding: nil) ⇒ Object 



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# File 'lib/chainer/dataset/convert.rb', line 9

def self.concat_examples(batch, device: nil, padding: nil)
  raise "batch is empty" if batch.size == 0
  device = device ? Chainer::Device.create(device) : Chainer::Device.default # takes care of int and nil
  first_elem = batch[0]

  if first_elem.kind_of?(Array)
    result = []
    unless padding.kind_of?(Array)
      padding = [padding] * first_elem.size
    end

    first_elem.size.times do |i|
      x = _concat_arrays(batch.map { |b| b[i] }, padding[i], device)
      result.push(to_device(device, x))
    end

    return result
  else
    return _concat_arrays(batch, padding, device)
  end
end

.to_device(device, x) ⇒ Object 



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# File 'lib/chainer/dataset/convert.rb', line 4

def self.to_device(device, x)
  # TODO(sonots): Implement after Cumo supports transferring between devices
  x
end