【PaddlePaddle Hackathon 3 No.12】为 Paddle 新增 pairwise_distance (#44161)

* add paddle.nn.functional.pairwise_distance (cattidea/Paddle#273)
* remove the test case for undefined behavior
Co-authored-by: NSigureMo <sigure.qaq@gmail.com>

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

@@ -20,24 +20,64 @@ import numpy as np
 import unittest
 
 
-def pairwise_distance(x, y, p=2.0, epsilon=1e-6, keepdim=False):
-    return np.linalg.norm(x - y, ord=p, axis=1, keepdims=keepdim)
+def np_pairwise_distance(x, y, p=2.0, epsilon=1e-6, keepdim=False):
+    distance = np.linalg.norm(x - y + epsilon, ord=p, axis=-1, keepdims=keepdim)
+    # Paddle currently has not supported for 0-d Tensors, so even if keep_dim is False,
+    # and neither x nor y is batched, a Tensor of shape (1, ) is returned
+    if distance.ndim == 0:
+        distance = np.expand_dims(distance, axis=0)
+    return distance
 
 
-def test_static(x_np, y_np, p=2.0, epsilon=1e-6, keepdim=False):
+def call_pairwise_distance_layer(x, y, p=2., epsilon=1e-6, keepdim='False'):
+    pairwise_distance = paddle.nn.PairwiseDistance(p=p,
+                                                   epsilon=epsilon,
+                                                   keepdim=keepdim)
+    distance = pairwise_distance(x=x, y=y)
+    return distance
+
+
+def call_pairwise_distance_functional(x,
+                                      y,
+                                      p=2.,
+                                      epsilon=1e-6,
+                                      keepdim='False'):
+    distance = paddle.nn.functional.pairwise_distance(x=x,
+                                                      y=y,
+                                                      p=p,
+                                                      epsilon=epsilon,
+                                                      keepdim=keepdim)
+    return distance
+
+
+def test_static(place,
+                x_np,
+                y_np,
+                p=2.0,
+                epsilon=1e-6,
+                keepdim=False,
+                functional=False):
     prog = paddle.static.Program()
     startup_prog = paddle.static.Program()
-
     place = fluid.CUDAPlace(
         0) if paddle.fluid.core.is_compiled_with_cuda() else fluid.CPUPlace()
-
+    paddle.enable_static()
     with paddle.static.program_guard(prog, startup_prog):
         x = paddle.fluid.data(name='x', shape=x_np.shape, dtype=x_np.dtype)
         y = paddle.fluid.data(name='y', shape=y_np.shape, dtype=x_np.dtype)
-        dist = paddle.nn.layer.distance.PairwiseDistance(p=p,
+
+        if functional:
+            distance = call_pairwise_distance_functional(x=x,
+                                                         y=y,
+                                                         p=p,
                                                          epsilon=epsilon,
                                                          keepdim=keepdim)
-        distance = dist(x, y)
+        else:
+            distance = call_pairwise_distance_layer(x=x,
+                                                    y=y,
+                                                    p=p,
+                                                    epsilon=epsilon,
+                                                    keepdim=keepdim)
         exe = paddle.static.Executor(place)
         static_ret = exe.run(prog,
                              feed={
@@ -46,69 +86,279 @@ def test_static(x_np, y_np, p=2.0, epsilon=1e-6, keepdim=False):
                              },
                              fetch_list=[distance])
         static_ret = static_ret[0]
+    paddle.disable_static()
     return static_ret
 
 
-def test_dygraph(x_np, y_np, p=2.0, epsilon=1e-6, keepdim=False):
-    paddle.disable_static()
+def test_dygraph(place,
+                 x_np,
+                 y_np,
+                 p=2.0,
+                 epsilon=1e-6,
+                 keepdim=False,
+                 functional=False):
     x = paddle.to_tensor(x_np)
     y = paddle.to_tensor(y_np)
-    dist = paddle.nn.layer.distance.PairwiseDistance(p=p,
-                                                     epsilon=epsilon,
-                                                     keepdim=keepdim)
-    distance = dist(x, y)
-    dygraph_ret = distance.numpy()
-    paddle.enable_static()
+    if functional:
+        dy_distance = call_pairwise_distance_functional(x=x,
+                                                        y=y,
+                                                        p=p,
+                                                        epsilon=epsilon,
+                                                        keepdim=keepdim)
+    else:
+        dy_distance = call_pairwise_distance_layer(x=x,
+                                                   y=y,
+                                                   p=p,
+                                                   epsilon=epsilon,
+                                                   keepdim=keepdim)
+    dygraph_ret = dy_distance.numpy()
     return dygraph_ret
 
 
+def test_legacy_dygraph(place,
+                        x_np,
+                        y_np,
+                        p=2.0,
+                        epsilon=1e-6,
+                        keepdim=False,
+                        functional=False):
+    paddle.fluid.framework._enable_legacy_dygraph()
+    x = paddle.to_tensor(x_np)
+    y = paddle.to_tensor(y_np)
+    if functional:
+        legacy_distance = call_pairwise_distance_functional(x=x,
+                                                            y=y,
+                                                            p=p,
+                                                            epsilon=epsilon,
+                                                            keepdim=keepdim)
+    else:
+        legacy_distance = call_pairwise_distance_layer(x=x,
+                                                       y=y,
+                                                       p=p,
+                                                       epsilon=epsilon,
+                                                       keepdim=keepdim)
+    legacy_ret = legacy_distance.numpy()
+    paddle.fluid.framework._disable_legacy_dygraph()
+    return legacy_ret
+
+
 class TestPairwiseDistance(unittest.TestCase):
 
     def test_pairwise_distance(self):
-        all_shape = [[100, 100], [4, 5, 6, 7]]
+        epsilon = 1e-6
+        all_shape = [[5], [100, 100]]
         dtypes = ['float32', 'float64']
+        p_list = [-1, 0, 1, 2, np.inf, -np.inf]
+        places = [paddle.CPUPlace()]
+        if paddle.device.is_compiled_with_cuda():
+            places.append(paddle.CUDAPlace(0))
         keeps = [False, True]
-        for shape in all_shape:
-            for dtype in dtypes:
-                for keepdim in keeps:
-                    x_np = np.random.random(shape).astype(dtype)
-                    y_np = np.random.random(shape).astype(dtype)
-
-                    static_ret = test_static(x_np, y_np, keepdim=keepdim)
-                    dygraph_ret = test_dygraph(x_np, y_np, keepdim=keepdim)
-                    excepted_value = pairwise_distance(x_np,
+        for place in places:
+            for shape in all_shape:
+                for dtype in dtypes:
+                    for p in p_list:
+                        for keepdim in keeps:
+                            x_np = np.random.random(shape).astype(dtype)
+                            y_np = np.random.random(shape).astype(dtype)
+
+                            static_ret = test_static(place,
+                                                     x_np,
+                                                     y_np,
+                                                     p,
+                                                     epsilon=epsilon,
+                                                     keepdim=keepdim)
+                            dygraph_ret = test_dygraph(place,
+                                                       x_np,
                                                        y_np,
+                                                       p,
+                                                       epsilon=epsilon,
                                                        keepdim=keepdim)
+                            legacy_ret = test_legacy_dygraph(place,
+                                                             x_np,
+                                                             y_np,
+                                                             p,
+                                                             epsilon=epsilon,
+                                                             keepdim=keepdim)
+                            excepted_value = np_pairwise_distance(
+                                x_np, y_np, p, epsilon=epsilon, keepdim=keepdim)
+
+                            self.assertEqual(static_ret.shape,
+                                             excepted_value.shape)
+                            self.assertEqual(dygraph_ret.shape,
+                                             excepted_value.shape)
+                            self.assertEqual(legacy_ret.shape,
+                                             excepted_value.shape)
+
+                            self.assertTrue(
+                                np.allclose(static_ret, excepted_value))
+                            self.assertTrue(
+                                np.allclose(dygraph_ret, excepted_value))
+                            self.assertTrue(
+                                np.allclose(legacy_ret, excepted_value))
+
+                            static_functional_ret = test_static(place,
+                                                                x_np,
+                                                                y_np,
+                                                                p,
+                                                                epsilon=epsilon,
+                                                                keepdim=keepdim)
+                            dygraph_functional_ret = test_dygraph(
+                                place,
+                                x_np,
+                                y_np,
+                                p,
+                                epsilon=epsilon,
+                                keepdim=keepdim)
+                            legacy_functional_ret = test_legacy_dygraph(
+                                place,
+                                x_np,
+                                y_np,
+                                p,
+                                epsilon=epsilon,
+                                keepdim=keepdim)
 
-                    self.assertTrue(np.allclose(static_ret, dygraph_ret))
-                    self.assertTrue(np.allclose(static_ret, excepted_value))
-                    self.assertTrue(np.allclose(dygraph_ret, excepted_value))
+                            self.assertEqual(static_functional_ret.shape,
+                                             excepted_value.shape)
+                            self.assertEqual(dygraph_functional_ret.shape,
+                                             excepted_value.shape)
+                            self.assertEqual(legacy_functional_ret.shape,
+                                             excepted_value.shape)
 
-    def test_pairwise_distance_broadcast(self):
+                            self.assertTrue(
+                                np.allclose(static_functional_ret,
+                                            excepted_value))
+                            self.assertTrue(
+                                np.allclose(dygraph_functional_ret,
+                                            excepted_value))
+                            self.assertTrue(
+                                np.allclose(legacy_functional_ret,
+                                            excepted_value))
+
+    def test_pairwise_distance_broadcast_1(self):
         shape_x = [100, 100]
         shape_y = [100, 1]
+        epsilon = 1e-6
         keepdim = False
+        place = paddle.CPUPlace()
         x_np = np.random.random(shape_x).astype('float32')
         y_np = np.random.random(shape_y).astype('float32')
-        static_ret = test_static(x_np, y_np, keepdim=keepdim)
-        dygraph_ret = test_dygraph(x_np, y_np, keepdim=keepdim)
-        excepted_value = pairwise_distance(x_np, y_np, keepdim=keepdim)
-        self.assertTrue(np.allclose(static_ret, dygraph_ret))
+        static_ret = test_static(place=place,
+                                 x_np=x_np,
+                                 y_np=y_np,
+                                 epsilon=epsilon,
+                                 keepdim=keepdim)
+        dygraph_ret = test_dygraph(place=place,
+                                   x_np=x_np,
+                                   y_np=y_np,
+                                   epsilon=epsilon,
+                                   keepdim=keepdim)
+        legacy_ret = test_legacy_dygraph(place=place,
+                                         x_np=x_np,
+                                         y_np=y_np,
+                                         epsilon=epsilon,
+                                         keepdim=keepdim)
+        excepted_value = np_pairwise_distance(x_np,
+                                              y_np,
+                                              epsilon=epsilon,
+                                              keepdim=keepdim)
+
+        self.assertEqual(static_ret.shape, excepted_value.shape)
+        self.assertEqual(dygraph_ret.shape, excepted_value.shape)
+        self.assertEqual(legacy_ret.shape, excepted_value.shape)
+
         self.assertTrue(np.allclose(static_ret, excepted_value))
         self.assertTrue(np.allclose(dygraph_ret, excepted_value))
+        self.assertTrue(np.allclose(legacy_ret, excepted_value))
+
+        static_functional_ret = test_static(place=place,
+                                            x_np=x_np,
+                                            y_np=y_np,
+                                            epsilon=epsilon,
+                                            keepdim=keepdim,
+                                            functional=True)
+        dygraph_functional_ret = test_dygraph(place=place,
+                                              x_np=x_np,
+                                              y_np=y_np,
+                                              epsilon=epsilon,
+                                              keepdim=keepdim,
+                                              functional=True)
+        legacy_functional_ret = test_legacy_dygraph(place=place,
+                                                    x_np=x_np,
+                                                    y_np=y_np,
+                                                    epsilon=epsilon,
+                                                    keepdim=keepdim,
+                                                    functional=True)
+
+        self.assertEqual(static_functional_ret.shape, excepted_value.shape)
+        self.assertEqual(dygraph_functional_ret.shape, excepted_value.shape)
+        self.assertEqual(legacy_functional_ret.shape, excepted_value.shape)
 
-    def test_pairwise_distance_different_p(self):
-        shape = [100, 100]
+        self.assertTrue(np.allclose(static_functional_ret, excepted_value))
+        self.assertTrue(np.allclose(dygraph_functional_ret, excepted_value))
+        self.assertTrue(np.allclose(legacy_functional_ret, excepted_value))
+
+    def test_pairwise_distance_broadcast_2(self):
+        shape_x = [100, 100]
+        shape_y = [100]
+        epsilon = 1e-6
         keepdim = False
-        p = 3.0
-        x_np = np.random.random(shape).astype('float32')
-        y_np = np.random.random(shape).astype('float32')
-        static_ret = test_static(x_np, y_np, p=p, keepdim=keepdim)
-        dygraph_ret = test_dygraph(x_np, y_np, p=p, keepdim=keepdim)
-        excepted_value = pairwise_distance(x_np, y_np, p=p, keepdim=keepdim)
-        self.assertTrue(np.allclose(static_ret, dygraph_ret))
+        place = paddle.CPUPlace()
+        x_np = np.random.random(shape_x).astype('float32')
+        y_np = np.random.random(shape_y).astype('float32')
+        static_ret = test_static(place=place,
+                                 x_np=x_np,
+                                 y_np=y_np,
+                                 epsilon=epsilon,
+                                 keepdim=keepdim)
+        dygraph_ret = test_dygraph(place=place,
+                                   x_np=x_np,
+                                   y_np=y_np,
+                                   epsilon=epsilon,
+                                   keepdim=keepdim)
+        legacy_ret = test_legacy_dygraph(place=place,
+                                         x_np=x_np,
+                                         y_np=y_np,
+                                         epsilon=epsilon,
+                                         keepdim=keepdim)
+        excepted_value = np_pairwise_distance(x_np,
+                                              y_np,
+                                              epsilon=epsilon,
+                                              keepdim=keepdim)
+
+        self.assertEqual(static_ret.shape, excepted_value.shape)
+        self.assertEqual(dygraph_ret.shape, excepted_value.shape)
+        self.assertEqual(legacy_ret.shape, excepted_value.shape)
+
         self.assertTrue(np.allclose(static_ret, excepted_value))
         self.assertTrue(np.allclose(dygraph_ret, excepted_value))
+        self.assertTrue(np.allclose(legacy_ret, excepted_value))
+
+        static_functional_ret = test_static(place=place,
+                                            x_np=x_np,
+                                            y_np=y_np,
+                                            epsilon=epsilon,
+                                            keepdim=keepdim,
+                                            functional=True)
+        dygraph_functional_ret = test_dygraph(place=place,
+                                              x_np=x_np,
+                                              y_np=y_np,
+                                              epsilon=epsilon,
+                                              keepdim=keepdim,
+                                              functional=True)
+        legacy_functional_ret = test_legacy_dygraph(place=place,
+                                                    x_np=x_np,
+                                                    y_np=y_np,
+                                                    epsilon=epsilon,
+                                                    keepdim=keepdim,
+                                                    functional=True)
+
+        self.assertEqual(static_functional_ret.shape, excepted_value.shape)
+        self.assertEqual(dygraph_functional_ret.shape, excepted_value.shape)
+        self.assertEqual(legacy_functional_ret.shape, excepted_value.shape)
+
+        self.assertTrue(np.allclose(static_functional_ret, excepted_value))
+        self.assertTrue(np.allclose(dygraph_functional_ret, excepted_value))
+        self.assertTrue(np.allclose(legacy_functional_ret, excepted_value))
 
 
 if __name__ == "__main__":

python/paddle/nn/functional/__init__.py

@@ -69,6 +69,7 @@ from .conv import conv2d  # noqa: F401
 from .conv import conv2d_transpose  # noqa: F401
 from .conv import conv3d  # noqa: F401
 from .conv import conv3d_transpose  # noqa: F401
+from .distance import pairwise_distance  # noqa: F401
 from .extension import diag_embed  # noqa: F401
 from .extension import sequence_mask
 from .loss import binary_cross_entropy  # noqa: F401
@@ -137,6 +138,7 @@ __all__ = [  # noqa
     'conv2d_transpose',
     'conv3d',
     'conv3d_transpose',
+    'pairwise_distance',
     'elu',
     'elu_',
     'gelu',

python/paddle/nn/functional/distance.py

+#   Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import paddle
+from ...fluid.data_feeder import check_variable_and_dtype, check_type
+from ...fluid.layer_helper import LayerHelper
+from paddle import _C_ops
+from paddle.fluid.framework import in_dygraph_mode, _in_legacy_dygraph
+
+__all__ = []
+
+
+def pairwise_distance(x, y, p=2., epsilon=1e-6, keepdim=False, name=None):
+    r"""
+    It computes the pairwise distance between two vectors. The
+    distance is calculated by p-oreder norm:
+
+    .. math::
+
+        \Vert x \Vert _p = \left( \sum_{i=1}^n \vert x_i \vert ^ p \right) ^ {1/p}.
+
+    Parameters:
+        x (Tensor): Tensor, shape is :math:`[N, D]` or :math:`[D]`, where :math:`N`
+            is batch size, :math:`D` is the dimension of vector. Available dtype is
+            float32, float64.
+        y (Tensor): Tensor, shape is :math:`[N, D]` or :math:`[D]`, where :math:`N`
+            is batch size, :math:`D` is the dimension of vector. Available dtype is
+            float32, float64.
+        p (float, optional): The order of norm. Default: :math:`2.0`.
+        epsilon (float, optional): Add small value to avoid division by zero.
+            Default: :math:`1e-6`.
+        keepdim (bool, optional): Whether to reserve the reduced dimension
+            in the output Tensor. The result tensor is one dimension less than
+            the result of ``|x-y|`` unless :attr:`keepdim` is True. Default: False.
+        name (str, optional): For details, please refer to :ref:`api_guide_Name`.
+            Generally, no setting is required. Default: None.
+
+    Returns:
+        Tensor, the dtype is same as input tensor.
+        - If :attr:`keepdim` is True, the output shape is :math:`[N, 1]` or :math:`[1]`,
+            depending on whether the input has data shaped as :math:`[N, D]`.
+        - If :attr:`keepdim` is False, the output shape is :math:`[N]` or :math:`[]`,
+            depending on whether the input has data shaped as :math:`[N, D]`.
+
+    Examples:
+        .. code-block:: python
+
+            import paddle
+            x = paddle.to_tensor([[1., 3.], [3., 5.]], dtype=paddle.float64)
+            y = paddle.to_tensor([[5., 6.], [7., 8.]], dtype=paddle.float64)
+            distance = paddle.nn.functional.pairwise_distance(x, y)
+            print(distance.numpy()) # [5. 5.]
+
+    """
+    check_type(p, 'porder', (float, int), 'PairwiseDistance')
+    check_type(epsilon, 'epsilon', (float), 'PairwiseDistance')
+    check_type(keepdim, 'keepdim', (bool), 'PairwiseDistance')
+    if in_dygraph_mode():
+        sub = _C_ops.elementwise_sub(x, y)
+        # p_norm op has not uesd epsilon, so change it to the following.
+        if epsilon != 0.0:
+            epsilon = paddle.fluid.dygraph.base.to_variable([epsilon],
+                                                            dtype=sub.dtype)
+            sub = _C_ops.elementwise_add(sub, epsilon)
+        return _C_ops.final_state_p_norm(sub, p, -1, 0., keepdim, False)
+
+    if _in_legacy_dygraph():
+        sub = _C_ops.elementwise_sub(x, y)
+        if epsilon != 0.0:
+            epsilon = paddle.fluid.dygraph.base.to_variable([epsilon],
+                                                            dtype=sub.dtype)
+            sub = _C_ops.elementwise_add(sub, epsilon)
+        return _C_ops.p_norm(sub, 'axis', -1, 'porder', p, 'keepdim', keepdim,
+                             'epsilon', 0.)
+
+    check_variable_and_dtype(x, 'x', ['float32', 'float64'], 'PairwiseDistance')
+    check_variable_and_dtype(y, 'y', ['float32', 'float64'], 'PairwiseDistance')
+    sub = paddle.subtract(x, y)
+    if epsilon != 0.0:
+        epsilon_var = sub.block.create_var(dtype=sub.dtype)
+        epsilon_var = paddle.full(shape=[1],
+                                  fill_value=epsilon,
+                                  dtype=sub.dtype)
+        sub = paddle.add(sub, epsilon_var)
+    helper = LayerHelper("PairwiseDistance", name=name)
+    attrs = {
+        'axis': -1,
+        'porder': p,
+        'keepdim': keepdim,
+        'epsilon': 0.,
+    }
+    out = helper.create_variable_for_type_inference(dtype=x.dtype)
+    helper.append_op(type='p_norm',
+                     inputs={'X': sub},
+                     outputs={'Out': out},
+                     attrs=attrs)
+
+    return out

python/paddle/nn/layer/distance.py

-#   Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
+#   Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -12,22 +12,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import numpy as np
-
-import paddle
 from .. import Layer
-from ...fluid.data_feeder import check_variable_and_dtype, check_type
-from ...fluid.layer_helper import LayerHelper
-from paddle import _C_ops
-from paddle import in_dynamic_mode
-from paddle.fluid.framework import in_dygraph_mode, _in_legacy_dygraph
+from .. import functional as F
 
 __all__ = []
 
 
 class PairwiseDistance(Layer):
     r"""
-    This operator computes the pairwise distance between two vectors. The
+    It computes the pairwise distance between two vectors. The
     distance is calculated by p-oreder norm:
 
     .. math::
@@ -35,33 +28,31 @@ class PairwiseDistance(Layer):
         \Vert x \Vert _p = \left( \sum_{i=1}^n \vert x_i \vert ^ p \right) ^ {1/p}.
 
     Parameters:
-        p (float): The order of norm. The default value is 2.
-        epsilon (float, optional): Add small value to avoid division by zero,
-            default value is 1e-6.
+        p (float, optional): The order of norm. Default: :math:`2.0`.
+        epsilon (float, optional): Add small value to avoid division by zero.
+            Default: :math:`1e-6`.
         keepdim (bool, optional): Whether to reserve the reduced dimension
             in the output Tensor. The result tensor is one dimension less than
-            the result of ``'x-y'`` unless :attr:`keepdim` is True, default
-            value is False.
-        name (str, optional): Name for the operation (optional, default is None).
-            For more information, please refer to :ref:`api_guide_Name`.
+            the result of ``|x-y|`` unless :attr:`keepdim` is True. Default: False.
+        name (str, optional): For details, please refer to :ref:`api_guide_Name`.
+            Generally, no setting is required. Default: None.
 
     Shape:
-        x: :math:`[N, D]` where `D` is the dimension of vector, available dtype
-            is float32, float64.
-        y: :math:`[N, D]`, y have the same shape and dtype as x.
-        out: :math:`[N]`. If :attr:`keepdim` is ``True``, the out shape is :math:`[N, 1]`.
-            The same dtype as input tensor.
+        x: :math:`[N, D]` or :math:`[D]`, where :math:`N` is batch size, :math:`D`
+            is the dimension of the data. Available data type is float32, float64.
+        y: :math:`[N, D]` or :math:`[D]`, y have the same dtype as x.
+        output: The same dtype as input tensor.
+            - If :attr:`keepdim` is True, the output shape is :math:`[N, 1]` or :math:`[1]`,
+                depending on whether the input has data shaped as :math:`[N, D]`.
+            - If :attr:`keepdim` is False, the output shape is :math:`[N]` or :math:`[]`,
+                depending on whether the input has data shaped as :math:`[N, D]`.
 
     Examples:
         .. code-block:: python
 
             import paddle
-            import numpy as np
-            paddle.disable_static()
-            x_np = np.array([[1., 3.], [3., 5.]]).astype(np.float64)
-            y_np = np.array([[5., 6.], [7., 8.]]).astype(np.float64)
-            x = paddle.to_tensor(x_np)
-            y = paddle.to_tensor(y_np)
+            x = paddle.to_tensor([[1., 3.], [3., 5.]], dtype=paddle.float64)
+            y = paddle.to_tensor([[5., 6.], [7., 8.]], dtype=paddle.float64)
             dist = paddle.nn.PairwiseDistance()
             distance = dist(x, y)
             print(distance.numpy()) # [5. 5.]
@@ -74,41 +65,11 @@ class PairwiseDistance(Layer):
         self.epsilon = epsilon
         self.keepdim = keepdim
         self.name = name
-        check_type(self.p, 'porder', (float, int), 'PairwiseDistance')
-        check_type(self.epsilon, 'epsilon', (float), 'PairwiseDistance')
-        check_type(self.keepdim, 'keepdim', (bool), 'PairwiseDistance')
 
     def forward(self, x, y):
-        if in_dygraph_mode():
-            sub = _C_ops.elementwise_sub(x, y)
-            return _C_ops.final_state_p_norm(sub, self.p, 1, self.epsilon,
-                                             self.keepdim, False)
-
-        if _in_legacy_dygraph():
-            sub = _C_ops.elementwise_sub(x, y)
-            return _C_ops.p_norm(sub, 'axis', 1, 'porder', self.p, 'keepdim',
-                                 self.keepdim, 'epsilon', self.epsilon)
-
-        check_variable_and_dtype(x, 'x', ['float32', 'float64'],
-                                 'PairwiseDistance')
-        check_variable_and_dtype(y, 'y', ['float32', 'float64'],
-                                 'PairwiseDistance')
-        sub = paddle.subtract(x, y)
-
-        helper = LayerHelper("PairwiseDistance", name=self.name)
-        attrs = {
-            'axis': 1,
-            'porder': self.p,
-            'keepdim': self.keepdim,
-            'epsilon': self.epsilon,
-        }
-        out = helper.create_variable_for_type_inference(dtype=x.dtype)
-        helper.append_op(type='p_norm',
-                         inputs={'X': sub},
-                         outputs={'Out': out},
-                         attrs=attrs)
 
-        return out
+        return F.pairwise_distance(x, y, self.p, self.epsilon, self.keepdim,
+                                   self.name)
 
     def extra_repr(self):
         main_str = 'p={p}'