Module: Chainer::Utils::Conv

Defined in:
lib/chainer/utils/conv.rb

Class Method Summary collapse

Class Method Details

.col2im(col, sy, sx, ph, pw, h, w, dy: 1, dx: 1) ⇒ Object 



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# File 'lib/chainer/utils/conv.rb', line 51

def self.col2im(col, sy, sx, ph, pw, h, w, dy: 1, dx: 1)
  n, c, kh, kw, out_h, out_w = col.shape
  img = col.class.zeros(n, c, h + 2 * ph + sy - 1, w + 2 * pw + sx - 1)
  kh.times do |j|
    jdy = j * dy
    j_lim = [jdy + sy * out_h, img.shape[2]].min
    kw.times do |i|
      idx = i * dx
      i_lim = [idx + sx * out_w, img.shape[3]].min
      img[nil, nil, (jdy...j_lim).step(sy), (idx...i_lim).step(sx)] += col[nil, nil, j, i, nil, nil]
    end
  end
  return img[nil, nil, (ph...(h + ph)), (pw...(w + pw))]
end

.get_conv_outsize(size, k, s, p, cover_all: false, d: 1) ⇒ Object 



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# File 'lib/chainer/utils/conv.rb', line 4

def self.get_conv_outsize(size, k, s, p, cover_all: false, d: 1)
  dk = k + (k - 1) * (d - 1)
  if cover_all
    (size + p * 2 - dk + s - 1).div(s) + 1
  else
    (size + p * 2 - dk).div(s) + 1
  end
end

.get_deconv_outsize(size, k, s, p, cover_all: false) ⇒ Object 



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# File 'lib/chainer/utils/conv.rb', line 13

def self.get_deconv_outsize(size, k, s, p, cover_all: false)
  if cover_all
    s * (size - 1) + k -s + 1 - 2 * p
  else
    s * (size - 1) + k - 2 * p
  end
end

.im2col(img, kh, kw, sy, sx, ph, pw, pval: 0, cover_all: false, dy: 1, dx: 1) ⇒ Object 



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# File 'lib/chainer/utils/conv.rb', line 21

def self.im2col(img, kh, kw, sy, sx, ph, pw, pval: 0, cover_all: false, dy: 1, dx: 1)
  n, c, h, w = img.shape

  out_h = self.get_conv_outsize(h, kh, sy, ph, cover_all: cover_all, d: dy)
  raise 'Height in the output should be positive.' if out_h <= 0
  out_w = self.get_conv_outsize(w, kw, sx, pw, cover_all: cover_all, d: dx)
  raise 'Width in the output should be positive.' if out_w <= 0

  # padding
  # TODO: ref: numpy.pad
  pad_bottom = ph + sy - 1
  pad_right = pw + sx - 1
  pad_img = img.class.new(n, c, (h + ph + pad_bottom), (w + pw + pad_right)).fill(pval)
  pad_img[nil, nil, ph...(ph+h), pw...(pw+w)] = img

  col = pad_img.class.new(n, c, kh, kw, out_h, out_w).rand(1)

  kh.times do |j|
    jdy = j * dy
    j_lim = [jdy + sy * out_h, pad_img.shape[2]].min
    kw.times do |i|
      idx = i * dx
      i_lim = [idx + sx * out_w, pad_img.shape[3]].min
      col[nil, nil, j, i, nil, nil] = pad_img[nil, nil, (jdy...j_lim).step(sy), (idx...i_lim).step(sx)]
    end
  end

  col
end