Merge pull request #14336 from jacquesqiao/add_bilinear_tensor_product_layer

add bilinear_tensor_product layer

Author: jacquesqiao

paddle/fluid/API.spec

@@ -184,6 +184,7 @@ paddle.fluid.layers.hash ArgSpec(args=['input', 'hash_size', 'num_hash', 'name']
 paddle.fluid.layers.grid_sampler ArgSpec(args=['x', 'grid', 'name'], varargs=None, keywords=None, defaults=(None,))
 paddle.fluid.layers.log_loss ArgSpec(args=['input', 'label', 'epsilon', 'name'], varargs=None, keywords=None, defaults=(0.0001, None))
 paddle.fluid.layers.add_position_encoding ArgSpec(args=['input', 'alpha', 'beta', 'name'], varargs=None, keywords=None, defaults=(None,))
+paddle.fluid.layers.bilinear_tensor_product ArgSpec(args=['x', 'y', 'size', 'act', 'name', 'param_attr', 'bias_attr'], varargs=None, keywords=None, defaults=(None, None, None, None))
 paddle.fluid.layers.data ArgSpec(args=['name', 'shape', 'append_batch_size', 'dtype', 'lod_level', 'type', 'stop_gradient'], varargs=None, keywords=None, defaults=(True, 'float32', 0, VarType.LOD_TENSOR, True))
 paddle.fluid.layers.open_files ArgSpec(args=['filenames', 'shapes', 'lod_levels', 'dtypes', 'thread_num', 'buffer_size', 'pass_num', 'is_test'], varargs=None, keywords=None, defaults=(None, None, 1, None))
 paddle.fluid.layers.read_file ArgSpec(args=['reader'], varargs=None, keywords=None, defaults=None)

python/paddle/fluid/layers/nn.py

@@ -165,6 +165,7 @@
     'grid_sampler',
     'log_loss',
     'add_position_encoding',
+    'bilinear_tensor_product',
 ]
 
 
@@ -8289,3 +8290,72 @@ def add_position_encoding(input, alpha, beta, name=None):
         attrs={"alpha": alpha,
                "beta": beta})
     return out
+
+
+def bilinear_tensor_product(x,
+                            y,
+                            size,
+                            act=None,
+                            name=None,
+                            param_attr=None,
+                            bias_attr=None):
+    """
+    **Add Bilinear Tensor Product Layer**
+
+    This layer performs bilinear tensor product on two inputs.
+    For example:
+
+    .. math::
+       out{i} = x * W_{i} * {y^\mathrm{T}}, i=0,1,...,size-1
+
+    In this formula:
+      - :math:`x`: the first input contains M elements, shape is [batch_size, M].
+      - :math:`y`: the second input contains N elements, shape is [batch_size, N].
+      - :math:`W_{i}`: the i-th learned weight, shape is [M, N]
+      - :math:`out{i}`: the i-th element of out, shape is [batch_size, size].
+      - :math:`y^\mathrm{T}`: the transpose of :math:`y_{2}`.
+
+    Args:
+        x (Variable): 2-D input tensor with shape [batch_size, M]
+        y (Variable): 2-D input tensor with shape [batch_size, N]
+        size (int): The dimension of this layer.
+        act (str, default None): Activation to be applied to the output of this layer.
+        name (str, default None): The name of this layer.
+        param_attr (ParamAttr, default None): The parameter attribute for the learnable w.
+            parameters/weights of this layer.
+        bias_attr (ParamAttr, default None): The parameter attribute for the bias
+            of this layer. If it is set to False, no bias will be added to the output units.
+            If it is set to None, the bias is initialized zero. Default: None.
+
+    Returns:
+        Variable: A 2-D Tensor of shape [batch_size, size].
+
+    Examples:
+        .. code-block:: python
+
+          tensor = bilinear_tensor_product(x=layer1, y=layer2, size=1000)
+    """
+    helper = LayerHelper('bilinear_tensor_product', **locals())
+    dtype = helper.input_dtype('x')
+
+    param_shape = [size, x.shape[1], y.shape[1]]
+
+    w = helper.create_parameter(
+        attr=helper.param_attr, shape=param_shape, dtype=dtype, is_bias=False)
+
+    if name is None:
+        out = helper.create_variable_for_type_inference(dtype=dtype)
+    else:
+        out = helper.create_variable(name=name, dtype=dtype, persistable=False)
+
+    inputs = {"X": x, "Y": y, "Weight": w}
+    if helper.bias_attr:
+        bias_size = [1, size]
+        bias = helper.create_parameter(
+            attr=helper.bias_attr, shape=bias_size, dtype=dtype, is_bias=True)
+        inputs["Bias"] = bias
+    helper.append_op(
+        type="bilinear_tensor_product", inputs=inputs, outputs={"Out": out})
+
+    # add activation
+    return helper.append_activation(out)

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

@@ -911,6 +911,16 @@ def test_affine_grid(self):
             self.assertIsNotNone(data_1)
         print(str(program))
 
+    def test_bilinear_tensor_product_layer(self):
+        program = Program()
+        with program_guard(program):
+            data = layers.data(name='data', shape=[4], dtype="float32")
+
+            theta = layers.data(name="theta", shape=[5], dtype="float32")
+            out = layers.bilinear_tensor_product(data, theta, 6)
+
+        print(str(program))
+
 
 if __name__ == '__main__':
     unittest.main()