def backward(self, gy):
# TODO(Koki): This is simple implementation
N, C, OH, OW = gy.shape
KW, KH = pair(self.kernel_size)
gy /= (KW*KH)
gcol = broadcast_to(gy.reshape(-1), (KH, KW, N*C*OH*OW))
gcol = gcol.reshape(KH, KW, N, C, OH, OW).transpose(2, 3, 0, 1, 4, 5)
gx = col2im(gcol, self.input_shape, self.kernel_size, self.stride,
self.pad, to_matrix=False)
return gx
def test_backward(self):
x = Variable(np.array([1, 2, 3]))
y = broadcast_to(x, (2, 3))
y.backward()
self.assertEqual(x.grad.shape, (3, ))
assert_equal(x.grad.data, np.array([2, 2, 2]))
def test_forward(self):
x = Variable(np.array([1, 2, 3]))
y = broadcast_to(x, (2, 3))
self.assertEqual(y.data.shape, (2, 3))
assert_equal(np.array([[1, 2, 3], [1, 2, 3]]), y.data)