Merge pull request #6792 from lcy-seso/refine_doc

Refine the doc for mul_op and fully connected layer.

doc/api/v2/config/layer.rst

@@ -467,7 +467,7 @@ lambda_cost
     :noindex:
 
 square_error_cost
---------
+-----------------
 ..  autoclass:: paddle.v2.layer.square_error_cost
     :noindex:
 
@@ -533,7 +533,7 @@ Miscs
 =====
 
 dropout
---------------
+--------
 ..  autoclass:: paddle.v2.layer.dropout
     :noindex:
 

doc/api/v2/fluid/layers.rst

@@ -19,17 +19,17 @@ dynamic_lstm
     :noindex:
 
 data
----------
+----
 ..  autofunction:: paddle.v2.fluid.layers.data
     :noindex:
 
 mean
----------
+----
 ..  autofunction:: paddle.v2.fluid.layers.mean
     :noindex:
 
 mul
----------
+---
 ..  autofunction:: paddle.v2.fluid.layers.mul
     :noindex:
 
@@ -45,13 +45,13 @@ elementwise_div
 
 
 dropout
----------
+-------
 ..  autofunction:: paddle.v2.fluid.layers.dropout
     :noindex:
 
 
 reshape
----------
+--------
 ..  autofunction:: paddle.v2.fluid.layers.reshape
     :noindex:
 
@@ -81,67 +81,67 @@ transpose
 
 
 sigmoid_cross_entropy_with_logits
----------
+---------------------------------
 ..  autofunction:: paddle.v2.fluid.layers.esigmoid_cross_entropy_with_logits
     :noindex:
 
 
 cast
----------
+----
 ..  autofunction:: paddle.v2.fluid.layers.cast
     :noindex:
 
 
 concat
----------
+-------
 ..  autofunction:: paddle.v2.fluid.layers.concat
     :noindex:
 
 
 sums
----------
+----
 ..  autofunction:: paddle.v2.fluid.layers.sums
     :noindex:
 
 
 linear_chain_crf
----------
+----------------
 ..  autofunction:: paddle.v2.fluid.layers.linear_chain_crf
     :noindex:
 
 
 assign
----------
+-------
 ..  autofunction:: paddle.v2.fluid.layers.embedding
     :noindex:
 
 
 split_lod_tensor
----------
+----------------
 ..  autofunction:: paddle.v2.fluid.layers.split_lod_tensor
     :noindex:
 
 
 merge_lod_tensor
----------
+----------------
 ..  autofunction:: paddle.v2.fluid.layers.merge_lod_tensor
     :noindex:
 
 cos_sim
----------
+--------
 ..  autofunction:: paddle.v2.fluid.layers.cos_sim
     :noindex:
 
 
 cross_entropy
----------
+-------------
 ..  autofunction:: paddle.v2.fluid.layers.cross_entropy
     :noindex:
 
 
 
 square_error_cost
----------
+-----------------
 ..  autofunction:: paddle.v2.fluid.layers.square_error_cost
     :noindex:
 
@@ -153,68 +153,68 @@ accuracy
 
 
 sequence_conv
----------
+-------------
 ..  autofunction:: paddle.v2.fluid.layers.sequence_conv
     :noindex:
 
 
 conv2d
----------
+------
 ..  autofunction:: paddle.v2.fluid.layers.conv2d
     :noindex:
 
 
 sequence_pool
----------
+-------------
 ..  autofunction:: paddle.v2.fluid.layers.sequence_pool
     :noindex:
 
 
 pool2d
----------
+------
 ..  autofunction:: paddle.v2.fluid.layers.pool2d
     :noindex:
 
 
 batch_norm
----------
+----------
 ..  autofunction:: paddle.v2.fluid.layers.batch_norm
     :noindex:
 
 
 beam_search_decode
----------
+------------------
 ..  autofunction:: paddle.v2.fluid.layers.beam_search_decode
     :noindex:
 
 
 lod_rank_table
----------
+--------------
 ..  autofunction:: paddle.v2.fluid.layers.lod_rank_table
     :noindex:
 
 
 max_sequence_len
----------
+----------------
 ..  autofunction:: paddle.v2.fluid.layers.max_sequence_len
     :noindex:
 
 
 topk
----------
+-----
 ..  autofunction:: paddle.v2.fluid.layers.topk
     :noindex:
 
 
 lod_tensor_to_array
----------
+-------------------
 ..  autofunction:: paddle.v2.fluid.layers.lod_tensor_to_array
     :noindex:
 
 
 
 array_to_lod_tensor
----------
+-------------------
 ..  autofunction:: paddle.v2.fluid.layers.array_to_lod_tensor
     :noindex:
 
@@ -222,26 +222,26 @@ array_to_lod_tensor
 
 
 fill_constant
----------
+-------------
 ..  autofunction:: paddle.v2.fluid.layers.fill_constant
     :noindex:
 
 
 
 fill_constant_batch_size_like
----------
+-----------------------------
 ..  autofunction:: paddle.v2.fluid.layers.fill_constant_batch_size_like
     :noindex:
 
 
 ones
----------
+----
 ..  autofunction:: paddle.v2.fluid.layers.ones
     :noindex:
 
 
 zeros
----------
+-----
 ..  autofunction:: paddle.v2.fluid.layers.zeros
     :noindex:
 
@@ -253,14 +253,14 @@ increment
 
 
 array_write
----------
+-----------
 ..  autofunction:: paddle.v2.fluid.layers.array_write
     :noindex:
 
 
 
 create_array
----------
+------------
 ..  autofunction:: paddle.v2.fluid.layers.create_array
     :noindex:
 
@@ -272,31 +272,31 @@ less_than
 
 
 array_read
----------
+----------
 ..  autofunction:: paddle.v2.fluid.layers.array_read
     :noindex:
 
 
 shrink_memory
----------
+--------------
 ..  autofunction:: paddle.v2.fluid.layers.shrink_memory
     :noindex:
 
 
 array_length
----------
+-------------
 ..  autofunction:: paddle.v2.fluid.layers.array_length
     :noindex:
 
 
 conv2d_transpose
----------
+----------------
 ..  autofunction:: paddle.v2.fluid.layers.conv2d_transpose
     :noindex:
 
 
 sequence_expand
----------
+---------------
 ..  autofunction:: paddle.v2.fluid.layers.sequence_expand
     :noindex:
 
@@ -308,13 +308,13 @@ lstm_unit
 
 
 sequence_softmax
----------
+----------------
 ..  autofunction:: paddle.v2.fluid.layers.sequence_softmax
     :noindex:
 
 
 reduce_sum
----------
+----------
 ..  autofunction:: paddle.v2.fluid.layers.reduce_sum
     :noindex:
 

doc/api/v2/fluid/nets.rst

@@ -3,19 +3,19 @@ Nets
 ===========
 
 simple_img_conv_pool
------------
+--------------------
 ..  autofunction:: paddle.v2.fluid.nets.simple_img_conv_pool
     :noindex:
 
 
 img_conv_group
------------
+---------------
 ..  autofunction:: paddle.v2.fluid.nets.img_conv_group
     :noindex:
 
 
 sequence_conv_pool
------------
+------------------
 ..  autofunction:: paddle.v2.fluid.nets.sequence_conv_pool
     :noindex:
 

doc/api/v2/fluid/optimizer.rst

@@ -18,7 +18,7 @@ SGDOptimizer
 
 
 MomentumOptimizer
------------
+-----------------
 ..  automodule:: paddle.v2.fluid.optimizer
     :members: MomentumOptimizer
     :noindex:
@@ -26,14 +26,14 @@ MomentumOptimizer
 
 
 AdagradOptimizer
------------
+----------------
 ..  automodule:: paddle.v2.fluid.optimizer
     :members: AdagradOptimizer
     :noindex:
 
 
 AdamOptimizer
------------
+-------------
 ..  automodule:: paddle.v2.fluid.optimizer
     :members: AdamOptimizer
     :noindex:
@@ -47,7 +47,7 @@ AdamaxOptimizer
 
 
 DecayedAdagradOptimizer
------------
+-----------------------
 ..  automodule:: paddle.v2.fluid.optimizer
     :members: DecayedAdagradOptimizer
     :noindex:

doc/api/v2/fluid/regularizer.rst

@@ -3,14 +3,14 @@ Regularizer
 ===========
 
 WeightDecayRegularizer
------------
+----------------------
 ..  automodule:: paddle.v2.fluid.regularizer
     :members: WeightDecayRegularizer
     :noindex:
 
 
 L2DecayRegularizer
------------
+------------------
 ..  automodule:: paddle.v2.fluid.regularizer
     :members: L2DecayRegularizer
     :noindex:
@@ -18,7 +18,7 @@ L2DecayRegularizer
 
 
 L1DecayRegularizer
------------
+-------------------
 ..  automodule:: paddle.v2.fluid.regularizer
     :members: L1DecayRegularizer
 

paddle/operators/mul_op.cc

@@ -73,39 +73,50 @@ class MulOpMaker : public framework::OpProtoAndCheckerMaker {
  public:
   MulOpMaker(OpProto* proto, OpAttrChecker* op_checker)
       : OpProtoAndCheckerMaker(proto, op_checker) {
-    AddInput("X", "The first input of mul op");
-    AddInput("Y", "The second input of mul op");
-    AddOutput("Out", "The output of mul op");
+    AddInput("X", "(Tensor), The first input tensor of mul op.");
+    AddInput("Y", "(Tensor), The second input tensor of mul op.");
+    AddOutput("Out", "(Tensor), The output tensor of mul op.");
     AddAttr<int>(
         "x_num_col_dims",
-        "(int, default 1) "
-        R"DOC(mul_op can take tensors with more than two dimensions as input `X`,
-            in that case, tensors will be reshaped to a matrix. The matrix's first
-            dimension(column length) will be the product of tensor's last
-            `num_col_dims` dimensions, and the matrix's second dimension(row length)
-            will be the product of tensor's first `rank - num_col_dims` dimensions.
+        R"DOC((int, default 1), The mul_op can take tensors with more than two
+              dimensions as its inputs. If the input $X$ is a tensor with more
+              than two dimensions, $X$ will be flattened into a two-dimensional
+              matrix first. The flattening rule is: the first `num_col_dims`
+              will be flattened to form the first dimension of the final matrix
+              (the height of the matrix), and the rest `rank(X) - num_col_dims`
+              dimensions are flattened to form the second dimension of the final
+              matrix (the width of the matrix). As a result, height of the
+              flattened matrix is equal to the product of $X$'s first
+              `x_num_col_dims` dimensions' sizes, and width of the flattened
+              matrix is equal to the product of $X$'s last `rank(x) - num_col_dims`
+              dimensions' size. For example, suppose $X$ is a 6-dimensional
+              tensor with the shape [2, 3, 4, 5, 6], and `x_num_col_dims` = 3.
+              Thus, the flattened matrix will have a shape [2 x 3 x 4, 5 x 6] =
+              [24, 30].
         )DOC")
         .SetDefault(1)
         .EqualGreaterThan(1);
     AddAttr<int>(
         "y_num_col_dims",
-        "(int, default 1) "
-        R"DOC(mul_op can take tensors with more than two dimensions as input `Y`,
-             in that case, tensors will be reshaped to a matrix. Just like input `X`.
+        R"DOC((int, default 1), The mul_op can take tensors with more than two,
+              dimensions as its inputs. If the input $Y$ is a tensor with more
+              than two dimensions, $Y$ will be flattened into a two-dimensional
+              matrix first. The attribute `y_num_col_dims` determines how $Y$ is
+              flattened. See comments of `x_num_col_dims` for more details.
         )DOC")
         .SetDefault(1)
         .EqualGreaterThan(1);
     AddComment(R"DOC(
 Mul Operator.
 
-This operator is used to perform matrix multiplication for input X and Y.
+This operator is used to perform matrix multiplication for input $X$ and $Y$.
 
 The equation is:
 
     $$Out = X * Y$$
 
-Both the input `X` and `Y` can carry the LoD (Level of Details) information,
-or not. But the output only shares the LoD information with input `X`.
+Both the input $X$ and $Y$ can carry the LoD (Level of Details) information,
+or not. But the output only shares the LoD information with input $X$.
 
 )DOC");
   }

python/paddle/v2/fluid/layers/nn.py

@@ -27,48 +27,81 @@ def fc(input,
     """
     **Fully Connected Layer**
 
-    This layer accepts multiple inputs and applies a linear transformation to each input.
-    If activation type is provided, the corresponding activation function is applied to the
-    output of the linear transformation. For each input :math:`X`, the equation is:
+    The fully connected layer can take multiple tensors as its inputs. It
+    creates a variable (one for each input tensor) called weights for each input
+    tensor, which represents a fully connected weight matrix from each input
+    unit to each output unit. The fully connected layer multiplies each input
+    tensor with its coresponding weight to produce an output Tensor. If
+    multiple input tensors are given, the results of multiple multiplications
+    will be sumed up. If bias_attr is not None, a biases variable will be
+    created and added to the output. Finally, if activation is not None,
+    it will be applied to the output as well.
+
+    This process can be formulated as follows:
 
     .. math::
 
-        Out = Act(WX + b)
+        Out = Act\left({\sum_{i=0}^{N-1}W_iX_i + b}\right)
 
     In the above equation:
 
-        * :math:`X`: Input value, a tensor with rank at least 2.
-        * :math:`W`: Weight, a 2-D tensor with shape [M, N].
-        * :math:`b`: Bias, a 2-D tensor with shape [M, 1].
-        * :math:`Act`: Activation function.
-        * :math:`Out`: Output value, same shape with :math:`X`.
-
-    All the input variables are passed in as local variables to the LayerHelper
-    constructor.
+    * :math:`N`: Number of the input.
+    * :math:`X_i`: The input tensor.
+    * :math:`W`: The weights created by this layer.
+    * :math:`b`: The bias parameter created by this layer (if needed).
+    * :math:`Act`: The activation funtion.
+    * :math:`Out`: The output tensor.
 
     Args:
-       input(Variable|list): Input tensors. Each tensor has a rank of atleast 2
-       size(int): Output size
-       num_flatten_dims(int): Number of columns in input
-       param_attr(ParamAttr|list): The parameters/weights to the FC Layer
-       bias_attr(ParamAttr|list): Bias parameter for the FC layer
-       act(str): Activation type
-       name(str): Name/alias of the function
+       input(Variable|list): The input tensor(s) to the fully connected layer.
+       size(int): The number of output units in the fully connected layer.
+       num_flatten_dims(int): The fc layer can accept an input tensor with more
+                              than two dimensions. If this happens, the
+                              multidimensional tensor will first be flattened
+                              into a 2-dimensional matrix. The parameter
+                              `num_flatten_dims` determines how the input tensor
+                              is flattened: the first `num_flatten_dims`
+                              dimensions will be flatten to form the first
+                              dimension of the final matrix (height of the
+                              matrix), and the rest `rank(X) - num_col_dims`
+                              dimensions are flattened to form the second
+                              dimension of the final matrix (width of the matrix).
+                              For example, suppose `X` is a 6-dimensional tensor
+                              with a shape [2, 3, 4, 5, 6], and
+                              `x_num_col_dims` = 3. Then, the flattened matrix
+                              will have a shape [2 x 3 x 4, 5 x 6] = [24, 30].
+                              By default, `x_num_col_dims` is set to 1.
+       param_attr(ParamAttr|list): The parameter attribute for learnable
+                                   parameters/weights of the fully connected
+                                   layer.
+       param_initializer(ParamAttr|list): The initializer used for the
+                                          weight/parameter. If set None,
+                                          XavierInitializer() will be used.
+       bias_attr(ParamAttr|list): The parameter attribute for the bias parameter
+                                  for this layer. If set None, no bias will be
+                                  added to the output units.
+       bias_initializer(ParamAttr|list): The initializer used for the bias.
+                                        If set None, then ConstantInitializer()
+                                        will be used.
+       act(str): Activation to be applied to the output of the fully connected
+                 layer.
+       name(str): Name/alias of the fully connected layer.
+
 
     Returns:
-        Variable: The tensor variable storing the transformation and \
-                  non-linearity activation result.
+        Variable: The output tensor variable.
 
     Raises:
-        ValueError: If rank of input tensor is less than 2.
+        ValueError: If rank of the input tensor is less than 2.
 
     Examples:
         .. code-block:: python
 
-          data = fluid.layers.data(name='data', shape=[32, 32], dtype='float32')
+          data = fluid.layers.data(name="data", shape=[32, 32], dtype="float32")
           fc = fluid.layers.fc(input=data, size=1000, act="tanh")
     """
-    helper = LayerHelper('fc', **locals())
+
+    helper = LayerHelper("fc", **locals())
 
     dtype = helper.input_dtype()
 
@@ -88,8 +121,8 @@ def fc(input,
                 "Y": w,
             },
             outputs={"Out": tmp},
-            attrs={'x_num_col_dims': num_flatten_dims,
-                   'y_num_col_dims': 1})
+            attrs={"x_num_col_dims": num_flatten_dims,
+                   "y_num_col_dims": 1})
         mul_results.append(tmp)
 
     # sum