add paddle.nn.functional.mse_loss (#26089)

* add paddle.nn.functional.mse_loss

* add name

* fix conflict

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

@@ -69,6 +69,7 @@ class TestNNMseLoss(unittest.TestCase):
         for dim in [[10, 10], [2, 10, 10], [3, 3, 10, 10]]:
             input_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
             label_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            paddle.enable_static()
             prog = fluid.Program()
             startup_prog = fluid.Program()
             place = fluid.CUDAPlace(0) if fluid.core.is_compiled_with_cuda(
@@ -106,6 +107,7 @@ class TestNNMseLoss(unittest.TestCase):
         for dim in [[10, 10], [2, 10, 10], [3, 3, 10, 10]]:
             input_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
             label_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            paddle.enable_static()
             prog = fluid.Program()
             startup_prog = fluid.Program()
             place = fluid.CUDAPlace(0) if fluid.core.is_compiled_with_cuda(
@@ -143,6 +145,7 @@ class TestNNMseLoss(unittest.TestCase):
         for dim in [[10, 10], [2, 10, 10], [3, 3, 10, 10]]:
             input_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
             label_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            paddle.enable_static()
             prog = fluid.Program()
             startup_prog = fluid.Program()
             place = fluid.CUDAPlace(0) if fluid.core.is_compiled_with_cuda(
@@ -177,5 +180,112 @@ class TestNNMseLoss(unittest.TestCase):
             self.assertTrue(dy_result.shape, [1])
 
 
+class TestNNFunctionalMseLoss(unittest.TestCase):
+    def test_NNFunctionalMseLoss_mean(self):
+        for dim in [[10, 10], [2, 10, 10], [3, 3, 10, 10]]:
+            input_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            target_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            paddle.enable_static()
+            prog = paddle.static.Program()
+            startup_prog = paddle.static.Program()
+            place = paddle.CUDAPlace(0) if core.is_compiled_with_cuda(
+            ) else paddle.CPUPlace()
+            with paddle.static.program_guard(prog, startup_prog):
+                input = paddle.data(name='input', shape=dim, dtype='float32')
+                target = paddle.data(name='target', shape=dim, dtype='float32')
+                mse_loss = paddle.nn.functional.mse_loss(input, target, 'mean')
+
+            exe = paddle.static.Executor(place)
+            exe.run(startup_prog)
+            static_result = exe.run(
+                prog,
+                feed={"input": input_np,
+                      "target": target_np},
+                fetch_list=[mse_loss])
+
+            paddle.disable_static()
+            dy_ret = paddle.nn.functional.mse_loss(
+                paddle.to_variable(input_np),
+                paddle.to_variable(target_np), 'mean')
+            dy_result = dy_ret.numpy()
+
+            sub = input_np - target_np
+            expected = np.mean(sub * sub)
+            self.assertTrue(np.allclose(static_result, expected))
+            self.assertTrue(np.allclose(static_result, dy_result))
+            self.assertTrue(np.allclose(dy_result, expected))
+            self.assertTrue(dy_result.shape, [1])
+
+    def test_NNFunctionalMseLoss_sum(self):
+        for dim in [[10, 10], [2, 10, 10], [3, 3, 10, 10]]:
+            input_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            target_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            paddle.enable_static()
+            prog = paddle.static.Program()
+            startup_prog = paddle.static.Program()
+            place = paddle.CUDAPlace(0) if core.is_compiled_with_cuda(
+            ) else paddle.CPUPlace()
+            with paddle.static.program_guard(prog, startup_prog):
+                input = paddle.data(name='input', shape=dim, dtype='float32')
+                target = paddle.data(name='target', shape=dim, dtype='float32')
+                mse_loss = paddle.nn.functional.mse_loss(input, target, 'sum')
+
+                exe = paddle.static.Executor(place)
+                exe.run(startup_prog)
+                static_result = exe.run(
+                    prog,
+                    feed={"input": input_np,
+                          "target": target_np},
+                    fetch_list=[mse_loss])
+
+            paddle.disable_static()
+            dy_ret = paddle.nn.functional.mse_loss(
+                paddle.to_variable(input_np),
+                paddle.to_variable(target_np), 'sum')
+            dy_result = dy_ret.numpy()
+
+            sub = input_np - target_np
+            expected = np.sum(sub * sub)
+            self.assertTrue(np.allclose(static_result, expected))
+            self.assertTrue(np.allclose(static_result, dy_result))
+            self.assertTrue(np.allclose(dy_result, expected))
+            self.assertTrue(dy_result.shape, [1])
+
+    def test_NNFunctionalMseLoss_none(self):
+        for dim in [[10, 10], [2, 10, 10], [3, 3, 10, 10]]:
+            input_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            target_np = np.random.uniform(0.1, 0.5, dim).astype("float32")
+            paddle.enable_static()
+            prog = paddle.static.Program()
+            startup_prog = paddle.static.Program()
+            place = paddle.CUDAPlace(0) if core.is_compiled_with_cuda(
+            ) else paddle.CPUPlace()
+            with paddle.static.program_guard(prog, startup_prog):
+                input = paddle.data(name='input', shape=dim, dtype='float32')
+                target = paddle.data(name='target', shape=dim, dtype='float32')
+                mse_loss = paddle.nn.functional.mse_loss(input, target, 'none')
+
+                exe = paddle.static.Executor(place)
+                exe.run(startup_prog)
+                static_result = exe.run(
+                    prog,
+                    feed={"input": input_np,
+                          "target": target_np},
+                    fetch_list=[mse_loss])
+
+            paddle.disable_static()
+            dy_ret = paddle.nn.functional.mse_loss(
+                paddle.to_variable(input_np),
+                paddle.to_variable(target_np), 'none')
+            dy_result = dy_ret.numpy()
+
+            sub = input_np - target_np
+            expected = sub * sub
+            self.assertTrue(np.allclose(static_result, expected))
+            self.assertTrue(np.allclose(static_result, dy_result))
+            self.assertTrue(np.allclose(dy_result, expected))
+            self.assertTrue(dy_result.shape, [1])
+
+
 if __name__ == "__main__":
     unittest.main()

python/paddle/nn/functional/loss.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import paddle
+
 # TODO: define loss functions of neural network  
 import numpy as np
 import paddle
@@ -25,7 +27,6 @@ from ...fluid.layers import dice_loss  #DEFINE_ALIAS
 from ...fluid.layers import iou_similarity  #DEFINE_ALIAS
 from ...fluid.layers import kldiv_loss  #DEFINE_ALIAS
 from ...fluid.layers import log_loss  #DEFINE_ALIAS
-from ...fluid.layers import mse_loss  #DEFINE_ALIAS
 from ...fluid.layers import npair_loss  #DEFINE_ALIAS
 from ...fluid.layers import rank_loss  #DEFINE_ALIAS
 from ...fluid.layers import reshape
@@ -371,3 +372,101 @@ def nll_loss(input,
         out = reshape(out, shape=out_shape)
 
     return out
+
+
+def mse_loss(input, label, reduction='mean', name=None):
+    """
+    This op accepts input predications and label and returns the mean square error.
+
+    If :attr:`reduction` is set to ``'none'``, loss is calculated as:
+
+    .. math::
+        Out = (input - label)^2
+
+    If :attr:`reduction` is set to ``'mean'``, loss is calculated as:
+
+    .. math::
+        Out = \operatorname{mean}((input - label)^2)
+
+    If :attr:`reduction` is set to ``'sum'``, loss is calculated as:
+
+    .. math::
+        Out = \operatorname{sum}((input - label)^2)
+
+    Parameters:
+        input (Tensor): Input tensor, the data type should be float32 or float64.
+        label (Tensor): Label tensor, the data type should be float32 or float64.
+        reduction (string, optional): The reduction method for the output,
+            could be 'none' | 'mean' | 'sum'.
+            If :attr:`reduction` is ``'mean'``, the reduced mean loss is returned.
+            If :attr:`reduction` is ``'sum'``, the reduced sum loss is returned.
+            If :attr:`reduction` is ``'none'``, the unreduced loss is returned.
+            Default is ``'mean'``.
+        name (str, optional): Name for the operation (optional, default is None). For more information, please refer to :ref:`api_guide_Name`.
+
+
+    Returns:
+        Tensor: The tensor tensor storing the mean square error difference of input and label.
+
+    Return type: Tensor.
+    
+    Examples:
+
+        .. code-block:: python
+            import numpy as np
+            import paddle
+
+
+            # static graph mode
+            paddle.enable_static()
+            mse_loss = paddle.nn.loss.MSELoss()
+            input = paddle.data(name="input", shape=[1])
+            label = paddle.data(name="label", shape=[1])
+            place = paddle.CPUPlace()
+            input_data = np.array([1.5]).astype("float32")
+            label_data = np.array([1.7]).astype("float32")
+
+            output = mse_loss(input,label)
+            exe = paddle.static.Executor(place)
+            exe.run(paddle.static.default_startup_program())
+            output_data = exe.run(
+                paddle.static.default_main_program(),
+                feed={"input":input_data, "label":label_data},
+                fetch_list=[output],
+                return_numpy=True)
+            print(output_data)
+            # [array([0.04000002], dtype=float32)]
+
+            # dynamic graph mode
+            paddle.disable_static()
+            input = paddle.to_variable(input_data)
+            label = paddle.to_variable(label_data)
+            output = mse_loss(input, label)
+            print(output.numpy())
+            # [0.04000002]
+
+    """
+
+    if reduction not in ['sum', 'mean', 'none']:
+        raise ValueError(
+            "'reduction' in 'mse_loss' should be 'sum', 'mean' or 'none', "
+            "but received {}.".format(reduction))
+
+    if not paddle.fluid.framework.in_dygraph_mode():
+        paddle.fluid.data_feeder.check_variable_and_dtype(
+            input, 'input', ['float32', 'float64'], 'mse_loss')
+        paddle.fluid.data_feeder.check_variable_and_dtype(
+            label, 'label', ['float32', 'float64'], 'mse_loss')
+
+    if reduction == 'none':
+        return paddle.fluid.layers.square(
+            paddle.fluid.layers.elementwise_sub(input, label), name=name)
+    elif reduction == 'mean':
+        return paddle.mean(
+            paddle.fluid.layers.square(
+                paddle.fluid.layers.elementwise_sub(input, label)),
+            name=name)
+    else:
+        return paddle.sum(paddle.fluid.layers.square(
+            paddle.fluid.layers.elementwise_sub(input, label)),
+                          name=name)