test_autograd.py 文件源码

def test_legacy_function_none_grad(self):
        class MyFunction(Function):
            def forward(self, x):
                return torch.zeros(2, 2, 2)

            def backward(self, grad_output):
                return None

        shape = (2, 3)
        v = Variable(torch.ones(shape), requires_grad=True)
        y = v[0, 0].expand(3, 5).t().sum()
        MyFunction()(y).sum().backward()
        self.assertEqual(v.grad.data, torch.zeros(shape))