diff --git a/python/paddle/fluid/layers/nn.py b/python/paddle/fluid/layers/nn.py index 679de6ce2aa67..2db4e5d27d40e 100644 --- a/python/paddle/fluid/layers/nn.py +++ b/python/paddle/fluid/layers/nn.py @@ -74,6 +74,7 @@ 'one_hot', 'autoincreased_step_counter', 'lod_reset', + 'lrn', ] @@ -3410,3 +3411,73 @@ def lod_reset(x, y=None, target_lod=None): raise ValueError("y and target_lod should not be both None.") return out + + +def lrn(input, n=5, k=1.0, alpha=1e-4, beta=0.75, name=None): + """ + Local Response Normalization Layer. This layer performs a type of + "lateral inhibition" by normalizing over local input regions. + + The formula is as follows: + + .. math:: + + Output(i, x, y) = Input(i, x, y) / \left( + k + \alpha \sum\limits^{\min(C, c + n/2)}_{j = \max(0, c - n/2)} + (Input(j, x, y))^2 \right)^{\beta} + + In the above equation: + + * :math:`n`: The number of channels to sum over. + * :math:`k`: The offset (avoid being divided by 0). + * :math:`alpha`: The scaling parameter. + * :math:`beta`: The exponent parameter. + + Refer to `ImageNet Classification with Deep Convolutional Neural Networks + `_ + + Args: + input (Variable): The input tensor of this layer, and the dimension of input tensor must be 4. + n (int, default 5): The number of channels to sum over. + k (float, default 1.0): An offset (usually positive to avoid dividing by 0). + alpha (float, default 1e-4): The scaling parameter. + beta (float, default 0.75): The exponent. + name (str, default None): A name for this operation. + + Raises: + ValueError: If rank of the input tensor is not 4. + + Returns: + A tensor variable storing the transformation result. + + Examples: + .. code-block:: python + + data = fluid.layers.data(name="data", shape=[3, 112, 112], dtype="float32") + lrn = fluid.layers.lrn(input=data) + """ + helper = LayerHelper('lrn', **locals()) + dtype = helper.input_dtype() + input_shape = input.shape + dims = len(input_shape) + + if dims != 4: + raise ValueError( + "dims of input must be 4(not %d), and it's order must be NCHW" % + (dims)) + + mid_out = helper.create_tmp_variable(dtype=dtype, stop_gradient=True) + lrn_out = helper.create_tmp_variable(dtype) + helper.append_op( + type="lrn", + inputs={"X": input}, + outputs={ + "Out": lrn_out, + "MidOut": mid_out, + }, + attrs={"n": n, + "k": k, + "alpha": alpha, + "beta": beta}) + + return lrn_out diff --git a/python/paddle/fluid/tests/unittests/test_layers.py b/python/paddle/fluid/tests/unittests/test_layers.py index b5fd59cf3a1be..2179826d81f71 100644 --- a/python/paddle/fluid/tests/unittests/test_layers.py +++ b/python/paddle/fluid/tests/unittests/test_layers.py @@ -231,6 +231,13 @@ def test_softmax(self): self.assertIsNotNone(layers.softmax(hid)) print(str(program)) + def test_lrn(self): + program = Program() + with program_guard(program): + data = layers.data(name='data', shape=[6, 2, 2], dtype='float32') + self.assertIsNotNone(layers.lrn(data)) + print(str(program)) + def test_get_places(self): program = Program() with program_guard(program):