Modified the return value of tensor.grad from numpy to tensor. (#32142)

* Modified the return value of tensor.grad from numpy as tensor.

* Modify unittests.

* fixed bugs.

* Add warning info for x.grad

* fixed unittests which used x.grad

* fixed bug.

python/paddle/fluid/dygraph/varbase_patch_methods.py

@@ -26,6 +26,7 @@ from .base import switch_to_static_graph
 from .math_op_patch import monkey_patch_math_varbase
 from .parallel import scale_loss
 from paddle.fluid.data_feeder import convert_dtype, _PADDLE_DTYPE_2_NUMPY_DTYPE
+import paddle.utils.deprecated as deprecated
 
 
 class TensorHookRemoveHelper(object):
@@ -238,8 +239,16 @@ def monkey_patch_varbase():
                 "Variable.backward() is only available in DyGraph mode")
 
     @framework.dygraph_only
+    @deprecated(
+        since="2.1.0",
+        reason="Please use x.grad, which returns the tensor value of the gradient."
+    )
     def gradient(self):
         """
+        .. warning::
+          This API will be deprecated in the future, it is recommended to use
+          :code:`x.grad` which returns the tensor value of the gradient.
+
         Get the Gradient of Current Tensor.
 
         Returns:
@@ -253,7 +262,7 @@ def monkey_patch_varbase():
                 x = paddle.to_tensor(5., stop_gradient=False)
                 y = paddle.pow(x, 4.0)
                 y.backward()
-                print("grad of x: {}".format(x.grad))
+                print("grad of x: {}".format(x.gradient()))
                 # [500.]
 
         """
@@ -337,10 +346,28 @@ def monkey_patch_varbase():
     @property
     def grad(self):
         """
-        The alias of gradient().
-        """
+        .. warning::
+          This API will return the tensor value of the gradient. If you want 
+          to get the numpy value of the gradient, you can use :code:`x.grad.numpy()`.
+
+        Get the Gradient of Current Tensor.
+
+        Returns:
+            Tensor: the gradient of current Tensor
 
-        return self.gradient()
+        Examples:
+            .. code-block:: python
+
+                import paddle
+
+                x = paddle.to_tensor(5., stop_gradient=False)
+                y = paddle.pow(x, 4.0)
+                y.backward()
+                print("grad of x: {}".format(x.grad))
+                # Tensor(shape=[1], dtype=float32, place=CUDAPlace(0), stop_gradient=False, [500.])
+
+        """
+        return self._grad_ivar()
 
     def clear_grad(self):
         """

python/paddle/fluid/tests/custom_op/test_custom_concat.py

@@ -58,7 +58,7 @@ def concat_dynamic(func, dtype, np_inputs, axis_v, with_attr=False):
     out = func(inputs, axis)
     out.stop_gradient = False
     out.backward()
-    grad_inputs = [x.grad for x in inputs]
+    grad_inputs = [x.grad.numpy() for x in inputs]
     return out.numpy(), grad_inputs
 
 

python/paddle/fluid/tests/custom_op/test_custom_conj.py

@@ -63,7 +63,10 @@ def conj_dynamic(func, dtype, np_input):
         sum_out.real().backward()
     else:
         sum_out.backward()
+    if x.grad is None:
         return out.numpy(), x.grad
+    else:
+        return out.numpy(), x.grad.numpy()
 
 
 def conj_static(func, shape, dtype, np_input):

python/paddle/fluid/tests/custom_op/test_custom_relu_op_setup.py

@@ -34,7 +34,10 @@ def custom_relu_dynamic(func, device, dtype, np_x, use_func=True):
 
     out.backward()
 
+    if t.grad is None:
         return out.numpy(), t.grad
+    else:
+        return out.numpy(), t.grad.numpy()
 
 
 def custom_relu_static(func,

python/paddle/fluid/tests/unittests/parallel_dygraph_gradient_check.py

@@ -110,7 +110,8 @@ class TestDistTraning(unittest.TestCase):
 
     def check_acc(self, grad, grad_sum, acc_grad):
         if grad is not None:
-            grad_sum = grad_sum + grad
+            grad_sum = grad_sum + grad.numpy()
+            acc_grad = acc_grad.numpy() if acc_grad is not None else None
             np.testing.assert_allclose(grad_sum, acc_grad, rtol=1e-6)
         return grad_sum
 

python/paddle/fluid/tests/unittests/test_base_layer.py

@@ -349,7 +349,8 @@ class TestLayerTo(unittest.TestCase):
                          paddle.fluid.core.VarDesc.VarType.FP64)
         self.assertEqual(self.linear.buf_name.dtype,
                          paddle.fluid.core.VarDesc.VarType.FP64)
-        self.assertTrue(np.allclose(self.linear.weight.grad, self.new_grad))
+        self.assertTrue(
+            np.allclose(self.linear.weight.grad.numpy(), self.new_grad))
         self.assertTrue(self.linear.weight._grad_ivar().dtype,
                         paddle.fluid.core.VarDesc.VarType.FP64)
 
@@ -358,7 +359,8 @@ class TestLayerTo(unittest.TestCase):
                          paddle.fluid.core.VarDesc.VarType.FP64)
         self.assertEqual(self.linear.buf_name.dtype,
                          paddle.fluid.core.VarDesc.VarType.FP64)
-        self.assertTrue(np.allclose(self.linear.weight.grad, self.new_grad))
+        self.assertTrue(
+            np.allclose(self.linear.weight.grad.numpy(), self.new_grad))
         self.assertTrue(self.linear.weight._grad_ivar().dtype,
                         paddle.fluid.core.VarDesc.VarType.FP64)
 

python/paddle/fluid/tests/unittests/test_custom_grad_input.py

@@ -46,7 +46,7 @@ class TestTensorBackward(unittest.TestCase):
 
                     x_grad = np.matmul(grad, y.T)
 
-                    self.assertTrue(np.allclose(x_grad, x_tensor.grad))
+                    self.assertTrue(np.allclose(x_grad, x_tensor.grad.numpy()))
 
 
 class TestBackwardAPI(unittest.TestCase):
@@ -75,7 +75,8 @@ class TestBackwardAPI(unittest.TestCase):
 
                     x_grad = np.matmul(grad, y.T)
 
-                    self.assertTrue(np.allclose(x_grad * 2, x_tensor.grad))
+                    self.assertTrue(
+                        np.allclose(x_grad * 2, x_tensor.grad.numpy()))
 
     def test_backward_single_tensor(self):
         for dtype in self._dtypes:
@@ -94,7 +95,7 @@ class TestBackwardAPI(unittest.TestCase):
 
                     x_grad = np.matmul(grad, y.T)
 
-                    self.assertTrue(np.allclose(x_grad, x_tensor.grad))
+                    self.assertTrue(np.allclose(x_grad, x_tensor.grad.numpy()))
 
     def test_backward_none_grad_tensor(self):
         for dtype in self._dtypes:
@@ -112,7 +113,7 @@ class TestBackwardAPI(unittest.TestCase):
 
                     x_grad = np.matmul(grad, y.T)
 
-                    self.assertTrue(np.allclose(x_grad, x_tensor.grad))
+                    self.assertTrue(np.allclose(x_grad, x_tensor.grad.numpy()))
 
 
 if __name__ == '__main__':

python/paddle/fluid/tests/unittests/test_imperative_basic.py

@@ -506,15 +506,15 @@ class TestImperative(unittest.TestCase):
             for i in range(10):
                 y = paddle.pow(x, 4.0)
                 y.backward()
-                self.assertEqual(x.grad, (i + 1) * 500)
+                self.assertEqual(x.grad.numpy(), (i + 1) * 500)
             x.clear_gradient()
-            self.assertEqual(x.grad, 0.)
+            self.assertEqual(x.grad.numpy(), 0.)
             for i in range(10):
                 y = paddle.pow(x, 4.0)
                 y.backward()
-                self.assertEqual(x.grad, (i + 1) * 500)
+                self.assertEqual(x.grad.numpy(), (i + 1) * 500)
             x.clear_grad()
-            self.assertEqual(x.grad, 0.)
+            self.assertEqual(x.grad.numpy(), 0.)
 
         def test_simple_net(sort_sum_gradient):
             fluid.set_flags({'FLAGS_sort_sum_gradient': sort_sum_gradient})
@@ -527,9 +527,9 @@ class TestImperative(unittest.TestCase):
                 loss2 = x * z
                 loss1.backward(retain_graph=True)
                 loss2.backward(retain_graph=True)
-                self.assertTrue(np.array_equal(x.grad, [23.]))
-                self.assertTrue(np.array_equal(y.grad, [25.]))
-                self.assertTrue(np.array_equal(z.grad, [5.]))
+                self.assertTrue(np.array_equal(x.grad.numpy(), [23.]))
+                self.assertTrue(np.array_equal(y.grad.numpy(), [25.]))
+                self.assertTrue(np.array_equal(z.grad.numpy(), [5.]))
                 x.clear_grad()
                 y.clear_grad()
                 z.clear_grad()
@@ -542,13 +542,13 @@ class TestImperative(unittest.TestCase):
             loss = fun(x, y, z)
             loss.backward(retain_graph=True)
             # x.grad = 2*x*y + z + 2*y = 27 
-            self.assertTrue(np.array_equal(x.grad, [27]))
+            self.assertTrue(np.array_equal(x.grad.numpy(), [27]))
 
             loss.backward(retain_graph=True)
-            self.assertTrue(np.array_equal(x.grad, [54]))
+            self.assertTrue(np.array_equal(x.grad.numpy(), [54]))
 
             loss.backward()
-            self.assertTrue(np.array_equal(x.grad, [81]))
+            self.assertTrue(np.array_equal(x.grad.numpy(), [81]))
 
             with self.assertRaises(RuntimeError):
                 loss.backward()
@@ -558,8 +558,8 @@ class TestImperative(unittest.TestCase):
             dx = paddle.grad([loss1], x, create_graph=True)[0]
             loss = loss1 + loss2 + dx
             loss.backward()
-            self.assertTrue(np.array_equal(dx.grad, [1]))
-            self.assertTrue(np.array_equal(x.grad, [108]))
+            self.assertTrue(np.array_equal(dx.grad.numpy(), [1]))
+            self.assertTrue(np.array_equal(x.grad.numpy(), [108]))
 
         def test_mlp(sort_sum_gradient):
             fluid.set_flags({'FLAGS_sort_sum_gradient': sort_sum_gradient})
@@ -579,28 +579,34 @@ class TestImperative(unittest.TestCase):
                 detach_x = x.detach()
                 clear_loss = mlp2(detach_x)
                 clear_loss.backward()
-                expected_weight1_grad = expected_weight1_grad + mlp2._linear1.weight.grad
-                expected_bias1_grad = expected_bias1_grad + mlp2._linear1.bias.grad
-                expected_weight2_grad = expected_weight2_grad + mlp2._linear2.weight.grad
-                expected_bias2_grad = expected_bias2_grad + mlp2._linear2.bias.grad
+                expected_weight1_grad = (
+                    expected_weight1_grad + mlp2._linear1.weight.grad.numpy())
+                expected_bias1_grad = (
+                    expected_bias1_grad + mlp2._linear1.bias.grad.numpy())
+                expected_weight2_grad = (
+                    expected_weight2_grad + mlp2._linear2.weight.grad.numpy())
+                expected_bias2_grad = (
+                    expected_bias2_grad + mlp2._linear2.bias.grad.numpy())
 
                 loss = mlp1(x)
                 loss.backward()
 
-                self.assertTrue(np.array_equal(loss.grad, [1]))
+                self.assertTrue(np.array_equal(loss.grad.numpy(), [1]))
                 self.assertTrue(
-                    np.allclose(mlp1._linear1.weight.grad,
+                    np.allclose(mlp1._linear1.weight.grad.numpy(),
                                 expected_weight1_grad))
                 self.assertTrue(
-                    np.allclose(mlp1._linear1.bias.grad, expected_bias1_grad))
+                    np.allclose(mlp1._linear1.bias.grad.numpy(),
+                                expected_bias1_grad))
                 self.assertTrue(
-                    np.allclose(mlp1._linear2.weight.grad,
+                    np.allclose(mlp1._linear2.weight.grad.numpy(),
                                 expected_weight2_grad))
                 self.assertTrue(
-                    np.allclose(mlp1._linear2.bias.grad, expected_bias2_grad))
+                    np.allclose(mlp1._linear2.bias.grad.numpy(),
+                                expected_bias2_grad))
 
                 mlp2.clear_gradients()
-                self.assertTrue(np.array_equal(clear_loss.grad, [1]))
+                self.assertTrue(np.array_equal(clear_loss.grad.numpy(), [1]))
                 if ((batch_id + 1) % 10) == 0:
                     mlp1.clear_gradients()
                     expected_weight1_grad = 0.

python/paddle/fluid/tests/unittests/test_inplace.py

@@ -177,7 +177,7 @@ class TestDygraphInplace(unittest.TestCase):
             var_d = var_c**2
             loss = var_d.sum()
             loss.backward()
-            grad_var_a_inplace = var_a.grad
+            grad_var_a_inplace = var_a.grad.numpy()
 
         with paddle.fluid.dygraph.guard():
             var_a = paddle.to_tensor(self.input_var_numpy).astype(self.dtype)
@@ -188,7 +188,7 @@ class TestDygraphInplace(unittest.TestCase):
             var_d = var_c**2
             loss = var_d.sum()
             loss.backward()
-            grad_var_a = var_a.grad
+            grad_var_a = var_a.grad.numpy()
 
         self.assertTrue(np.array_equal(grad_var_a_inplace, grad_var_a))
 
@@ -209,7 +209,7 @@ class TestDygraphInplace(unittest.TestCase):
             loss = var_d.sum()
 
             loss.backward()
-            grad_var_a_inplace = var_a.grad
+            grad_var_a_inplace = var_a.grad.numpy()
 
         with paddle.fluid.dygraph.guard():
             var_a = paddle.to_tensor(self.input_var_numpy).astype(self.dtype)
@@ -224,7 +224,7 @@ class TestDygraphInplace(unittest.TestCase):
             loss = var_d.sum()
 
             loss.backward()
-            grad_var_a = var_a.grad
+            grad_var_a = var_a.grad.numpy()
         self.assertTrue(np.array_equal(grad_var_a_inplace, grad_var_a))
 
 

python/paddle/fluid/tests/unittests/test_lookahead.py

@@ -110,7 +110,8 @@ class TestLookAhead(unittest.TestCase):
                     out = layer(image)
                     loss = loss_fn(out, label)
                     loss.backward()
-                    fast_param = layer.bias.numpy() - SGD_LR * layer.bias.grad
+                    fast_param = (
+                        layer.bias.numpy() - SGD_LR * layer.bias.grad.numpy())
                     opt.step()
                     if idx == 1:
                         slow_param = fast_param

python/paddle/fluid/tests/unittests/test_pylayer_op.py

@@ -50,7 +50,8 @@ class TestPyLayer(unittest.TestCase):
         z2 = paddle.tanh(input2) + paddle.tanh(input2)
         z2.mean().backward()
 
-        self.assertTrue(np.max(np.abs((input1.grad - input2.grad))) < 1e-10)
+        self.assertTrue(
+            np.max(np.abs((input1.grad.numpy() - input2.grad.numpy()))) < 1e-10)
 
     def test_simple_pylayer_return_none_with_no_grad(self):
         class tanh(PyLayer):
@@ -110,7 +111,8 @@ class TestPyLayer(unittest.TestCase):
         z2 = paddle.tanh(input2)
         z2.mean().backward()
 
-        self.assertTrue(np.max(np.abs((input1.grad - input2.grad))) < 1e-10)
+        self.assertTrue(
+            np.max(np.abs((input1.grad.numpy() - input2.grad.numpy()))) < 1e-10)
 
     def test_pylayer_dtype(self):
         class tanh(PyLayer):

python/paddle/fluid/tests/unittests/test_tensor_register_hook.py

@@ -75,15 +75,15 @@ class TestTensorRegisterHook(unittest.TestCase):
                 o.backward()
 
                 # z.grad is not affected
-                self.assertTrue(np.array_equal(z.grad, w.numpy()))
+                self.assertTrue(np.array_equal(z.grad.numpy(), w.numpy()))
                 # w.grad is not changed by hook
-                self.assertTrue(np.array_equal(w.grad, z.numpy()))
+                self.assertTrue(np.array_equal(w.grad.numpy(), z.numpy()))
                 # x.grad and y.grad are changed if run hook
                 self.assertTrue(
-                    np.array_equal(x.grad,
+                    np.array_equal(x.grad.numpy(),
                                    z.numpy() * 2 if not removed else z.numpy()))
                 self.assertTrue(
-                    np.array_equal(y.grad,
+                    np.array_equal(y.grad.numpy(),
                                    z.numpy() * 2 if not removed else z.numpy()))
 
         def run_print_hook_for_interior_var(print_hook, removed=False):
@@ -111,10 +111,10 @@ class TestTensorRegisterHook(unittest.TestCase):
                 o.backward()
 
                 # all grads are not affected
-                self.assertTrue(np.array_equal(z.grad, w.numpy()))
-                self.assertTrue(np.array_equal(w.grad, z.numpy()))
-                self.assertTrue(np.array_equal(x.grad, z.numpy()))
-                self.assertTrue(np.array_equal(y.grad, z.numpy()))
+                self.assertTrue(np.array_equal(z.grad.numpy(), w.numpy()))
+                self.assertTrue(np.array_equal(w.grad.numpy(), z.numpy()))
+                self.assertTrue(np.array_equal(x.grad.numpy(), z.numpy()))
+                self.assertTrue(np.array_equal(y.grad.numpy(), z.numpy()))
 
         def double_hook(grad):
             grad = grad * 2
@@ -165,12 +165,12 @@ class TestTensorRegisterHook(unittest.TestCase):
                 o.backward()
 
                 # z.grad, w.grad, x.grad is not affected
-                self.assertTrue(np.array_equal(z.grad, w.numpy()))
-                self.assertTrue(np.array_equal(w.grad, z.numpy()))
-                self.assertTrue(np.array_equal(x.grad, z.numpy()))
+                self.assertTrue(np.array_equal(z.grad.numpy(), w.numpy()))
+                self.assertTrue(np.array_equal(w.grad.numpy(), z.numpy()))
+                self.assertTrue(np.array_equal(x.grad.numpy(), z.numpy()))
                 # y.grad are changed if run hook
                 self.assertTrue(
-                    np.array_equal(y.grad,
+                    np.array_equal(y.grad.numpy(),
                                    z.numpy() * 2 if not removed else z.numpy()))
 
         # register hook
@@ -217,14 +217,14 @@ class TestTensorRegisterHook(unittest.TestCase):
 
                 base_grad = np.array([5., 9., 13., 19.])
                 # x.grad is not changed
-                self.assertTrue(np.array_equal(x.grad, base_grad))
+                self.assertTrue(np.array_equal(x.grad.numpy(), base_grad))
                 # b.grad is changed by x.hook
                 self.assertTrue(
-                    np.array_equal(b.grad, base_grad * 2
+                    np.array_equal(b.grad.numpy(), base_grad * 2
                                    if not removed else base_grad))
                 # a.grad is changed by x.hook and a.hook
                 self.assertTrue(
-                    np.array_equal(a.grad, base_grad * 4
+                    np.array_equal(a.grad.numpy(), base_grad * 4
                                    if not removed else base_grad))
 
         # register hook
@@ -265,7 +265,7 @@ class TestTensorRegisterHook(unittest.TestCase):
                 base_grad = np.array([5., 9., 13., 19.])
                 # x.grad is changed by x.hook
                 self.assertTrue(
-                    np.array_equal(x.grad, base_grad * 2
+                    np.array_equal(x.grad.numpy(), base_grad * 2
                                    if not removed else base_grad))
 
         # register hook
@@ -294,7 +294,8 @@ class TestTensorRegisterHook(unittest.TestCase):
                 loss = loss_fn(out, label)
                 loss.backward()
 
-                return ret1.grad, net.linear1.weight.grad, net.linear1.bias.grad
+                return (ret1.grad.numpy(), net.linear1.weight.grad.numpy(),
+                        net.linear1.bias.grad.numpy())
 
         data = np.random.uniform(
             size=[self.batch_size, self.in_size]).astype('float32')
@@ -355,7 +356,7 @@ class TestTensorRegisterHook(unittest.TestCase):
 
             o.backward()
 
-            return z.numpy(), w.grad, x.grad, y.grad
+            return z.numpy(), w.grad.numpy(), x.grad.numpy(), y.grad.numpy()
 
         def double_hook(grad):
             return grad * 2
@@ -428,7 +429,7 @@ class TestTensorRegisterHook(unittest.TestCase):
         # after changed by hook: 8.0
 
         z.backward()
-        self.assertTrue(np.array_equal(x.grad, np.array([8.])))
+        self.assertTrue(np.array_equal(x.grad.numpy(), np.array([8.])))
 
     def test_remove_one_hook_multiple_times(self):
         for device in self.devices:

python/paddle/fluid/tests/unittests/test_var_base.py

@@ -65,7 +65,8 @@ class TestVarBase(unittest.TestCase):
                 y = clone_x**2
                 y.backward()
                 self.assertTrue(
-                    np.array_equal(x.grad, np.array([2.4]).astype('float32')))
+                    np.array_equal(x.grad.numpy(),
+                                   np.array([2.4]).astype('float32')))
                 y = x.cpu()
                 self.assertEqual(y.place.__repr__(), "CPUPlace")
                 if core.is_compiled_with_cuda():
@@ -260,14 +261,14 @@ class TestVarBase(unittest.TestCase):
 
             y = x**2
             y.backward()
-            self.assertTrue(np.array_equal(x.grad, [20.0]))
+            self.assertTrue(np.array_equal(x.grad.numpy(), [20.0]))
             self.assertEqual(detach_x.grad, None)
 
             detach_x.stop_gradient = False  # Set stop_gradient to be False, supported auto-grad
             z = 3 * detach_x**2
             z.backward()
-            self.assertTrue(np.array_equal(x.grad, [20.0]))
-            self.assertTrue(np.array_equal(detach_x.grad, [60.0]))
+            self.assertTrue(np.array_equal(x.grad.numpy(), [20.0]))
+            self.assertTrue(np.array_equal(detach_x.grad.numpy(), [60.0]))
 
             # Due to sharing of data with origin Tensor, There are some unsafe operations:
             with self.assertRaises(RuntimeError):