test_function.py 文件源码

def test_backward(self):
        x = chainer.Variable(numpy.array([1]), name='x')
        y1 = F.identity(x)
        y1.name = 'y1'
        y2 = F.identity(x)
        y2.name = 'y2'
        z = y1 + y2
        z.name = 'z'

        z.grad = numpy.array([1])
        z.backward(retain_grad=True)

        self.assertEqual(y1.grad[0], 1)
        self.assertEqual(y2.grad[0], 1)
        self.assertEqual(x.grad[0], 2)