Dev/add l1 loss (#23322)

* add L1Loss

* support L1Loss, test=develop

* add test, test=develop

* fix batch, test=develop

* follow comments, test=develop

python/paddle/__init__.py

@@ -33,6 +33,7 @@ import paddle.compat
 import paddle.distributed
 batch = batch.batch
 import paddle.sysconfig
+import paddle.nn
 
 #TODO: define alias in tensor and framework directory
 # from .tensor.creation import create_.tensor   #DEFINE_ALIAS

python/paddle/fluid/tests/unittests/test_l1_loss.py

@@ -0,0 +1,131 @@
+# Copyright (c) 2020 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.
+
+from __future__ import print_function
+
+import paddle
+import paddle.fluid as fluid
+import numpy as np
+import unittest
+
+
+class TestL1Loss(unittest.TestCase):
+    def test_L1Loss_mean(self):
+        input_np = np.random.random(size=(10, 1)).astype(np.float32)
+        label_np = np.random.random(size=(10, 1)).astype(np.float32)
+        prog = fluid.Program()
+        startup_prog = fluid.Program()
+        place = fluid.CUDAPlace(0) if fluid.core.is_compiled_with_cuda(
+        ) else fluid.CPUPlace()
+        with fluid.program_guard(prog, startup_prog):
+            input = fluid.layers.data(
+                name='input', shape=[10, 1], dtype='float32')
+            label = fluid.layers.data(
+                name='label', shape=[10, 1], dtype='float32')
+            l1_loss = paddle.nn.loss.L1Loss()
+            ret = l1_loss(input, label)
+
+            exe = fluid.Executor(place)
+            static_result = exe.run(
+                prog,
+                feed={"input": input_np,
+                      "label": label_np},
+                fetch_list=[ret])
+
+        with fluid.dygraph.guard():
+            l1_loss = paddle.nn.loss.L1Loss()
+            dy_ret = l1_loss(
+                fluid.dygraph.to_variable(input_np),
+                fluid.dygraph.to_variable(label_np))
+            dy_result = dy_ret.numpy()
+
+        expected = np.mean(np.abs(input_np - label_np))
+        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_L1Loss_sum(self):
+        input_np = np.random.random(size=(10, 10, 5)).astype(np.float32)
+        label_np = np.random.random(size=(10, 10, 5)).astype(np.float32)
+        prog = fluid.Program()
+        startup_prog = fluid.Program()
+        place = fluid.CUDAPlace(0) if fluid.core.is_compiled_with_cuda(
+        ) else fluid.CPUPlace()
+        with fluid.program_guard(prog, startup_prog):
+            input = fluid.layers.data(
+                name='input', shape=[10, 10, 5], dtype='float32')
+            label = fluid.layers.data(
+                name='label', shape=[10, 10, 5], dtype='float32')
+            l1_loss = paddle.nn.loss.L1Loss(reduction='sum')
+            ret = l1_loss(input, label)
+
+            exe = fluid.Executor(place)
+            static_result = exe.run(
+                prog,
+                feed={"input": input_np,
+                      "label": label_np},
+                fetch_list=[ret])
+
+        with fluid.dygraph.guard():
+            l1_loss = paddle.nn.loss.L1Loss(reduction='sum')
+            dy_ret = l1_loss(
+                fluid.dygraph.to_variable(input_np),
+                fluid.dygraph.to_variable(label_np))
+            dy_result = dy_ret.numpy()
+
+        expected = np.sum(np.abs(input_np - label_np))
+        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_L1Loss_none(self):
+        input_np = np.random.random(size=(10, 5)).astype(np.float32)
+        label_np = np.random.random(size=(10, 5)).astype(np.float32)
+        prog = fluid.Program()
+        startup_prog = fluid.Program()
+        place = fluid.CUDAPlace(0) if fluid.core.is_compiled_with_cuda(
+        ) else fluid.CPUPlace()
+        with fluid.program_guard(prog, startup_prog):
+            input = fluid.layers.data(
+                name='input', shape=[10, 5], dtype='float32')
+            label = fluid.layers.data(
+                name='label', shape=[10, 5], dtype='float32')
+            l1_loss = paddle.nn.loss.L1Loss(reduction='none')
+            ret = l1_loss(input, label)
+
+            exe = fluid.Executor(place)
+            static_result = exe.run(
+                prog,
+                feed={"input": input_np,
+                      "label": label_np},
+                fetch_list=[ret])
+
+        with fluid.dygraph.guard():
+            l1_loss = paddle.nn.loss.L1Loss(reduction='none')
+            dy_ret = l1_loss(
+                fluid.dygraph.to_variable(input_np),
+                fluid.dygraph.to_variable(label_np))
+            dy_result = dy_ret.numpy()
+
+        expected = np.abs(input_np - label_np)
+        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, input.shape)
+
+
+if __name__ == "__main__":
+    unittest.main()

python/paddle/nn/__init__.py

@@ -14,7 +14,7 @@
 
 # TODO: import all neural network related api under this directory, 
 # including layers, linear, conv, rnn etc.
-# __all__ = [ ]
+__all__ = []
 
 # TODO: define alias in nn directory
 # from .clip import ErrorClipByValue   #DEFINE_ALIAS
@@ -56,7 +56,8 @@
 # from .layer.loss import NCELoss   #DEFINE_ALIAS
 # from .layer.loss import CrossEntropyLoss   #DEFINE_ALIAS
 # from .layer.loss import MSELoss   #DEFINE_ALIAS
-# from .layer.loss import L1Loss   #DEFINE_ALIAS
+from .layer.loss import L1Loss  #DEFINE_ALIAS
+from .layer import loss  #DEFINE_ALIAS
 # from .layer.loss import NLLLoss   #DEFINE_ALIAS
 # from .layer.loss import BCELoss   #DEFINE_ALIAS
 # from .layer.learning_rate import CosineDecay   #DEFINE_ALIAS

python/paddle/nn/layer/__init__.py

@@ -0,0 +1,18 @@
+#   Copyright (c) 2020 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.
+
+# TODO: define activation functions of neural network  
+
+from . import loss
+__all__ = [loss]

python/paddle/nn/layer/loss.py

@@ -13,9 +13,99 @@
 # limitations under the License.
 
 # TODO: define loss functions of neural network  
-# __all__ = ['NCELoss',
+import paddle.fluid as fluid
-#            'CrossEntropyLoss',
+__all__ = [
-#            'MSELoss',
+    #'NCELoss',
-#            'L1Loss',
+    #    'CrossEntropyLoss',
-#            'NLLLoss',
+    #    'MSELoss',
-#            'BCELoss']
+    'L1Loss',
+    #    'NLLLoss',
+    #   'BCELoss'
+]
+
+
+class L1Loss(fluid.dygraph.Layer):
+    """
+    This interface is used to construct a callable object of the ``L1Loss`` class.
+    The L1Loss layer calculates the L1 Loss of input predictions and target 
+    labels as follows.
+
+    If :attr:`reduction` set to ``'none'``, the unreduced loss is:
+    .. math::
+        Out = |input - label|
+    If :attr:`reduction` set to ``'mean'``, the reduced mean loss is:
+    .. math::
+        Out = MEAN(|input - label|)
+    If :attr:`reduction` set to ``'sum'``, the reduced sum loss is:
+    .. math::
+        Out = SUM(|input - label|)
+
+    The shape of input predictions and target labels are [N, *], where N is batch_size and `*` 
+    means any number of additional dimensions.
+    If :attr:`reduction` is ``'none'``, the shape of output loss is [N, *], the same as input.
+    If :attr:`reduction` is ``'mean'`` or ``'sum'``, the shape of output loss is [1], which means the output is a scalar.
+    
+    Parameters:
+        reduction (str, optional): Indicate the reduction to apply to the loss, 
+            the candicates are ``'none'`` | ``'mean'`` | ``'sum'``.
+            If :attr:`reduction` is ``'none'``, the unreduced loss is returned; 
+            If :attr:`reduction` is ``'mean'``, the reduced mean loss is returned. 
+            If :attr:`reduction` is ``'sum'``, the reduced sum loss is returned. 
+            Default is ``'mean'``.
+    Returns:
+        A callable object of L1Loss.
+    Examples:
+        .. code-block:: python
+            # declarative mode
+            import paddle.fluid as fluid
+            import numpy as np
+            import paddle
+            input = fluid.data(name="input", shape=[1])
+            label = fluid.data(name="label", shape=[1])
+            l1_loss = paddle.nn.loss.L1Loss(reduction='mean')
+            output = l1_loss(input,label)
+            place = fluid.CPUPlace()
+            exe = fluid.Executor(place)
+            exe.run(fluid.default_startup_program())
+    
+            input_data = np.array([1.5]).astype("float32")
+            label_data = np.array([1.7]).astype("float32")
+            output_data = exe.run(fluid.default_main_program(),
+                    feed={"input":input_data, "label":label_data},
+                    fetch_list=[output],
+                    return_numpy=True)
+    
+            print(output_data)  # [array([0.2], dtype=float32)]
+            
+            # imperative mode
+            import paddle.fluid.dygraph as dg
+            with dg.guard(place) as g:
+                input = dg.to_variable(input_data)
+                label = dg.to_variable(label_data)
+                l1_loss = paddle.nn.loss.L1Loss(reduction='mean')
+                output = l1_loss(input,label)
+                print(output.numpy())  # [0.2]
+    """
+
+    def __init__(self, reduction='mean'):
+        if reduction not in ['sum', 'mean', 'none']:
+            raise ValueError(
+                "The value of 'reduction' in L1Loss should be 'sum', 'mean' or 'none', but "
+                "received %s, which is not allowed." % reduction)
+        super(L1Loss, self).__init__()
+        self.reduction = reduction
+
+    def forward(self, input, label):
+        fluid.data_feeder.check_variable_and_dtype(
+            input, 'input', ['float32', 'float64', 'int32', 'int64'], 'l1_loss')
+        fluid.data_feeder.check_variable_and_dtype(
+            label, 'label', ['float32', 'float64', 'int32', 'int64'], 'l1_loss')
+
+        unreduced = fluid.layers.elementwise_sub(input, label, act='abs')
+
+        if self.reduction == 'sum':
+            return fluid.layers.reduce_sum(unreduced)
+        elif self.reduction == 'mean':
+            return fluid.layers.reduce_mean(unreduced)
+        else:
+            return unreduced

python/setup.py.in

@@ -105,6 +105,8 @@ write_version_py(filename='@PADDLE_BINARY_DIR@/python/paddle/version.py')
 
 
 packages=['paddle',
+          'paddle.nn',
+          'paddle.nn.layer',
           'paddle.libs',
           'paddle.utils',
           'paddle.dataset',