test_autograd.py 文件源码

def _test_setitem_tensor(self, size, index):
        x = Variable(torch.ones(*size), requires_grad=True)
        y = x + 2
        y_version = y._version
        value = Variable(torch.Tensor(x[index].size()).fill_(7), requires_grad=True)
        y[index] = value
        self.assertNotEqual(y._version, y_version)
        y.backward(torch.ones(*size))
        expected_grad_input = torch.ones(*size)
        if isinstance(index, Variable):
            index = index.data
        expected_grad_input[index] = 0
        self.assertEqual(x.grad.data, expected_grad_input)
        self.assertEqual(value.grad.data, torch.ones(value.size()))

        # case when x is not same shape as y[1]
        x = Variable(torch.randn(1, 2), requires_grad=True)
        y = Variable(torch.zeros(10, 2))
        y[1] = x
        y.backward(torch.randn(10, 2))
        self.assertEqual(x.size(), x.grad.size())