Modify English documents (#20452)

paddle/fluid/API.spec

@@ -9,7 +9,7 @@ paddle.fluid.Program.parse_from_string (ArgSpec(args=['binary_str'], varargs=Non
 paddle.fluid.Program.to_string (ArgSpec(args=['self', 'throw_on_error', 'with_details'], varargs=None, keywords=None, defaults=(False,)), ('document', '7dde33f16b63aa50d474870a9cebb539'))
 paddle.fluid.default_startup_program (ArgSpec(args=[], varargs=None, keywords=None, defaults=None), ('document', 'f53890b2fb8c0642b6047e4fee2d6d58'))
 paddle.fluid.default_main_program (ArgSpec(args=[], varargs=None, keywords=None, defaults=None), ('document', '082aa471d247bd8d7c87814105439e1a'))
-paddle.fluid.program_guard (ArgSpec(args=['main_program', 'startup_program'], varargs=None, keywords=None, defaults=(None,)), ('document', '78fb5c7f70ef76bcf4a1862c3f6b8191'))
+paddle.fluid.program_guard (ArgSpec(args=['main_program', 'startup_program'], varargs=None, keywords=None, defaults=(None,)), ('document', 'eb4eabc13405a8c6dc2f14308ddf5ed8'))
 paddle.fluid.name_scope (ArgSpec(args=['prefix'], varargs=None, keywords=None, defaults=(None,)), ('document', '907a5f877206079d8e67ae69b06bb3ba'))
 paddle.fluid.cuda_places (ArgSpec(args=['device_ids'], varargs=None, keywords=None, defaults=(None,)), ('document', 'ab9bd2079536114aa7c1488a489ee87f'))
 paddle.fluid.cpu_places (ArgSpec(args=['device_count'], varargs=None, keywords=None, defaults=(None,)), ('document', 'a7352a3dd39308fde4fbbf6421a4193d'))
@@ -72,24 +72,24 @@ paddle.fluid.BuildStrategy.ReduceStrategy.__init__ __init__(self: paddle.fluid.c
 paddle.fluid.BuildStrategy.__init__ __init__(self: paddle.fluid.core_avx.ParallelExecutor.BuildStrategy) -> None
 paddle.fluid.gradients (ArgSpec(args=['targets', 'inputs', 'target_gradients', 'no_grad_set'], varargs=None, keywords=None, defaults=(None, None)), ('document', 'e2097e1e0ed84ae44951437bfe269a1b'))
 paddle.fluid.io.save_vars (ArgSpec(args=['executor', 'dirname', 'main_program', 'vars', 'predicate', 'filename'], varargs=None, keywords=None, defaults=(None, None, None, None)), ('document', '9ff7159eef501e9dfaf520073e681c10'))
-paddle.fluid.io.save_params (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', '046d7c43d67e08c2660bb3bd7e081015'))
-paddle.fluid.io.save_persistables (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', 'ffcee38044975c29f2ab2fec0576f963'))
+paddle.fluid.io.save_params (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', 'a03d0de7594d311103671b7275f1b464'))
+paddle.fluid.io.save_persistables (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', '3cd8facbe536a09310e95453914ca322'))
 paddle.fluid.io.load_vars (ArgSpec(args=['executor', 'dirname', 'main_program', 'vars', 'predicate', 'filename'], varargs=None, keywords=None, defaults=(None, None, None, None)), ('document', '12dd2c3f29d63f7a920bb1e0a0e8caff'))
 paddle.fluid.io.load_params (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', 'f3f16db75ae076d46608c7e976650cfc'))
 paddle.fluid.io.load_persistables (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', '1e039084ad3781eb43966581eed48688'))
-paddle.fluid.io.save_inference_model (ArgSpec(args=['dirname', 'feeded_var_names', 'target_vars', 'executor', 'main_program', 'model_filename', 'params_filename', 'export_for_deployment', 'program_only'], varargs=None, keywords=None, defaults=(None, None, None, True, False)), ('document', 'fc82bfd137a9b1ab8ebd1651bd35b6e5'))
+paddle.fluid.io.save_inference_model (ArgSpec(args=['dirname', 'feeded_var_names', 'target_vars', 'executor', 'main_program', 'model_filename', 'params_filename', 'export_for_deployment', 'program_only'], varargs=None, keywords=None, defaults=(None, None, None, True, False)), ('document', '827797614e194d31ceb5a3a68c46efab'))
 paddle.fluid.io.load_inference_model (ArgSpec(args=['dirname', 'executor', 'model_filename', 'params_filename', 'pserver_endpoints'], varargs=None, keywords=None, defaults=(None, None, None)), ('document', '7a863032bf7613dec1c8dd99efbd82e5'))
-paddle.fluid.io.batch (ArgSpec(args=['reader', 'batch_size', 'drop_last'], varargs=None, keywords=None, defaults=(False,)), ('document', 'cf2869b408b39cadadd95206b4e03b39'))
+paddle.fluid.io.batch (ArgSpec(args=['reader', 'batch_size', 'drop_last'], varargs=None, keywords=None, defaults=(False,)), ('document', '16acb4e1215d5fc4386add454e717440'))
 paddle.fluid.io.save (ArgSpec(args=['program', 'model_path'], varargs=None, keywords=None, defaults=None), ('document', 'cef7d50c36b93c02b6d12bcea7d025ce'))
 paddle.fluid.io.load (ArgSpec(args=['program', 'model_path'], varargs=None, keywords=None, defaults=None), ('document', '8d0f200c20f8a4581e1843967230ad45'))
-paddle.fluid.io.PyReader ('paddle.fluid.reader.PyReader', ('document', 'b03399246f69cd6fc03b43e87af8bd4e'))
+paddle.fluid.io.PyReader ('paddle.fluid.reader.PyReader', ('document', 'f5875acee86f9f4432933bab40873722'))
 paddle.fluid.io.PyReader.__init__ (ArgSpec(args=['self', 'feed_list', 'capacity', 'use_double_buffer', 'iterable', 'return_list'], varargs=None, keywords=None, defaults=(None, None, True, True, False)), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
-paddle.fluid.io.PyReader.decorate_batch_generator (ArgSpec(args=['self', 'reader', 'places'], varargs=None, keywords=None, defaults=(None,)), ('document', '4364e836e3cb8ab5e68e411b763c50c7'))
-paddle.fluid.io.PyReader.decorate_sample_generator (ArgSpec(args=['self', 'sample_generator', 'batch_size', 'drop_last', 'places'], varargs=None, keywords=None, defaults=(True, None)), ('document', 'efa4c8b90fe6d99dcbda637b70351bb1'))
-paddle.fluid.io.PyReader.decorate_sample_list_generator (ArgSpec(args=['self', 'reader', 'places'], varargs=None, keywords=None, defaults=(None,)), ('document', '6c11980092720de304863de98074a64a'))
+paddle.fluid.io.PyReader.decorate_batch_generator (ArgSpec(args=['self', 'reader', 'places'], varargs=None, keywords=None, defaults=(None,)), ('document', '386f969058852594b916be7cc15b8066'))
+paddle.fluid.io.PyReader.decorate_sample_generator (ArgSpec(args=['self', 'sample_generator', 'batch_size', 'drop_last', 'places'], varargs=None, keywords=None, defaults=(True, None)), ('document', 'c3ab4fd82a4560e369adcd23a36c2a7b'))
+paddle.fluid.io.PyReader.decorate_sample_list_generator (ArgSpec(args=['self', 'reader', 'places'], varargs=None, keywords=None, defaults=(None,)), ('document', '182443165b1b6a607ca821052b1b9085'))
 paddle.fluid.io.PyReader.next (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', '08b2fd1463f3ea99d79d17303988349b'))
-paddle.fluid.io.PyReader.reset (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', '7432197701fdaab1848063860dc0b97e'))
-paddle.fluid.io.PyReader.start (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', 'a0983fb21a0a51e6a31716009fe9a9c1'))
+paddle.fluid.io.PyReader.reset (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', '259e025143f0bb7cfc6d7163bc333679'))
+paddle.fluid.io.PyReader.start (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', 'c91176b919e19be11cbc11ab3d47318e'))
 paddle.fluid.io.DataLoader ('paddle.fluid.reader.DataLoader', ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
 paddle.fluid.io.DataLoader.__init__ 
 paddle.fluid.io.DataLoader.from_dataset (ArgSpec(args=['dataset', 'places', 'drop_last'], varargs=None, keywords=None, defaults=(True,)), ('document', 'eb8b6d31e1c2ec2ca8ebbb62fcf46557'))
@@ -310,10 +310,10 @@ paddle.fluid.layers.hard_swish (ArgSpec(args=['x', 'threshold', 'scale', 'offset
 paddle.fluid.layers.gather_tree (ArgSpec(args=['ids', 'parents'], varargs=None, keywords=None, defaults=None), ('document', '201b54fa7512305078c70a6610beaead'))
 paddle.fluid.layers.mse_loss (ArgSpec(args=['input', 'label'], varargs=None, keywords=None, defaults=None), ('document', '88b967ef5132567396062d5d654b3064'))
 paddle.fluid.layers.uniform_random (ArgSpec(args=['shape', 'dtype', 'min', 'max', 'seed'], varargs=None, keywords=None, defaults=('float32', -1.0, 1.0, 0)), ('document', '34e7c1ff0263baf9551000b6bb3bc47e'))
-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)), ('document', '9d7806e31bdf727c1a23b8782a09b545'))
+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)), ('document', 'a43c597ac4e1cec20cf193c083d946be'))
 paddle.fluid.layers.read_file (ArgSpec(args=['reader'], varargs=None, keywords=None, defaults=None), ('document', 'd5b41c7b2df1b064fbd42dcf435268cd'))
 paddle.fluid.layers.double_buffer (ArgSpec(args=['reader', 'place', 'name'], varargs=None, keywords=None, defaults=(None, None)), ('document', '556fa82daf62cbb0fb393f4125daba77'))
-paddle.fluid.layers.py_reader (ArgSpec(args=['capacity', 'shapes', 'dtypes', 'lod_levels', 'name', 'use_double_buffer'], varargs=None, keywords=None, defaults=(None, None, True)), ('document', 'd78a1c7344955c5caed8dc13adb7beb6'))
+paddle.fluid.layers.py_reader (ArgSpec(args=['capacity', 'shapes', 'dtypes', 'lod_levels', 'name', 'use_double_buffer'], varargs=None, keywords=None, defaults=(None, None, True)), ('document', 'c9c52b0a57e541d751e7a839ad26ee1a'))
 paddle.fluid.layers.create_py_reader_by_data (ArgSpec(args=['capacity', 'feed_list', 'name', 'use_double_buffer'], varargs=None, keywords=None, defaults=(None, True)), ('document', '1321d4ce89d82f96fcfd5601f816b0f3'))
 paddle.fluid.layers.load (ArgSpec(args=['out', 'file_path', 'load_as_fp16'], varargs=None, keywords=None, defaults=(None,)), ('document', '309f9e5249463e1b207a7347b2a91134'))
 paddle.fluid.layers.create_tensor (ArgSpec(args=['dtype', 'name', 'persistable'], varargs=None, keywords=None, defaults=(None, False)), ('document', 'fdc2d964488e99fb0743887454c34e36'))

python/paddle/batch.py

@@ -17,16 +17,39 @@ __all__ = ['batch']
 
 def batch(reader, batch_size, drop_last=False):
     """
-    Create a batched reader.
-
-    :param reader: the data reader to read from.
-    :type reader: callable
-    :param batch_size: size of each mini-batch
-    :type batch_size: int
-    :param drop_last: drop the last batch, if the size of last batch is not equal to batch_size.
-    :type drop_last: bool
-    :return: the batched reader.
-    :rtype: callable
+    This operator creates a batched reader which combines the data from the 
+    input reader to batched data.
+    
+    Args:
+        reader(generator): the data reader to read from.
+        batch_size(int): size of each mini-batch.
+        drop_last(bool, optional): If set to True, the last batch is dropped when 
+            the size of last batch is not equal to batch_size, if set to False,
+            it will not. Default: False.
+    Returns:
+        The batched reader. 
+    
+    Return Type:
+        generator   
+
+    Examples:
+        .. code-block:: python
+           
+            import paddle.fluid as fluid
+            def reader():
+                for i in range(10):
+                    yield i
+            batch_reader = fluid.io.batch(reader, batch_size=2)
+            
+            for data in batch_reader():
+                print(data)
+
+            # Output is
+            # [0, 1]
+            # [2, 3]
+            # [4, 5]
+            # [6, 7]
+            # [8, 9]
     """
 
     def batch_reader():

python/paddle/fluid/framework.py

@@ -4626,6 +4626,13 @@ def program_guard(main_program, startup_program=None):
     Layer functions in the Python `"with"` block will append operators and
     variables to the new main programs.
 
+    Args:
+        main_program(Program): New main program inside `"with"` statement.
+        startup_program(Program, optional): New startup program inside `"with"` 
+            statement. :code:`None` means not changing startup program, 
+            default_startup_program is still used.
+            Default: None.
+
     Examples:
        .. code-block:: python
        
@@ -4634,7 +4641,7 @@ def program_guard(main_program, startup_program=None):
          main_program = fluid.Program()
          startup_program = fluid.Program()
          with fluid.program_guard(main_program, startup_program):
-             data = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
+             data = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
              hidden = fluid.layers.fc(input=data, size=10, act='relu')
 
     Notes: The temporary :code:`Program` can be used if the user does not need
@@ -4648,12 +4655,8 @@ def program_guard(main_program, startup_program=None):
          main_program = fluid.Program()
          # does not care about startup program. Just pass a temporary value.
          with fluid.program_guard(main_program, fluid.Program()):
-             data = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
+             data = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
     
-    Args:
-        main_program(Program): New main program inside `"with"` statement.
-        startup_program(Program): New startup program inside `"with"` statement.
-            None means not changing startup program.
     """
     if not isinstance(main_program, Program):
         raise TypeError("main_program should be Program")

python/paddle/fluid/io.py

@@ -258,30 +258,38 @@ def save_vars(executor,
 
 def save_params(executor, dirname, main_program=None, filename=None):
     """
-    This function filters out all parameters from the give `main_program`
-    and then save them to the folder `dirname` or the file `filename`.
+    This operator saves all parameters from the :code:`main_program` to
+    the folder :code:`dirname` or file :code:`filename`. You can refer to 
+    :ref:`api_guide_model_save_reader_en` for more details.
 
-    Use the `dirname` to specify the saving folder. If you would like to
-    save parameters in separate files, set `filename` None; if you would
-    like to save all parameters in a single file, use `filename` to specify
+    Use the :code:`dirname` to specify the saving folder. If you would like to
+    save parameters in separate files, set :code:`filename` None; if you would
+    like to save all parameters in a single file, use :code:`filename` to specify
     the file name.
 
-    NOTICE: Some variables are not Parameter while they are necessary for
-    training. So you can NOT save and continue your training just by
-    `save_params()` and `load_params()`. Please use `save_persistables()`
-    and `load_persistables()` instead. If you want to save your model for
-    the inference, please use the `save_inference_model` API. You can refer
-    to :ref:`api_guide_model_save_reader_en` for more details.
+    Note: 
+        Some variables are not Parameter while they are necessary for
+        training, such as learning rate, global step, etc. So you can NOT save 
+        and continue your training just by :ref:`api_fluid_io_save_params`
+        and :ref:`api_fluid_io_load_params`. Please use :ref:`api_fluid_io_save_persistables`
+        and :ref:`api_fluid_io_load_persistables` instead. 
+        
+        If you want to save your model for the inference, please use the 
+        :ref:`api_fluid_io_save_inference_model`. You can refer to
+        :ref:`api_guide_model_save_reader_en` for more details.
 
     Args:
-        executor(Executor): The executor to run for saving parameters.
+        executor(Executor): The executor to run for saving parameters, You can 
+                            refer to :ref:`api_guide_executor_en`.
         dirname(str): The saving directory path.
-        main_program(Program|None): The program whose parameters will be
-                                    saved. If it is None, the default
-                                    main program will be used automatically.
+        main_program(Program, optional): The program whose parameters will be
+                                         saved. You can refer to 
+                                         :ref:`api_guide_Program_en` for more 
+                                         details. If it is None, the default main
+                                         program will be used.
                                          Default: None
-        filename(str|None): The file to save all parameters. If you prefer
-                            to save parameters in differnet files, set it
+        filename(str, optional): The file to save all parameters. If you prefer
+                                 to save parameters in different files, set it
                                  to None.
                                  Default: None
 
@@ -293,11 +301,20 @@ def save_params(executor, dirname, main_program=None, filename=None):
 
             import paddle.fluid as fluid
            
+            params_path = "./my_paddle_model"
+            image = fluid.data(name='img', shape=[None, 28, 28], dtype='float32')
+            label = fluid.data(name='label', shape=[None, 1], dtype='int64')
+            feeder = fluid.DataFeeder(feed_list=[image, label], place=fluid.CPUPlace())
+            predict = fluid.layers.fc(input=image, size=10, act='softmax')
+    
+            loss = fluid.layers.cross_entropy(input=predict, label=label)
+            avg_loss = fluid.layers.mean(loss)
+            
             exe = fluid.Executor(fluid.CPUPlace())
-            param_path = "./my_paddle_model"
-            prog = fluid.default_main_program()
-            fluid.io.save_params(executor=exe, dirname=param_path,
-                                 main_program=None)
+            exe.run(fluid.default_startup_program())
+            fluid.io.save_params(executor=exe, dirname=params_path)
+            # The parameters weights and bias of the fc layer in the network are going to 
+            # be saved in different files in the path "./my_paddle_model" 
     """
     save_vars(
         executor,
@@ -491,25 +508,31 @@ def _save_distributed_persistables(executor, dirname, main_program):
 
 def save_persistables(executor, dirname, main_program=None, filename=None):
     """
-    This function filters out all variables with `persistable==True` from the
-    give `main_program` and then saves these variables to the folder `dirname`
-    or file `filename`.
+    This operator saves all persistable variables from :code:`main_program` to 
+    the folder :code:`dirname` or file :code:`filename`. You can refer to 
+    :ref:`api_guide_model_save_reader_en` for more details. And then
+    saves these persistables variables to the folder :code:`dirname` or file 
+    :code:`filename`. 
 
-    The `dirname` is used to specify the folder where persistable variables
+    The :code:`dirname` is used to specify the folder where persistable variables
     are going to be saved. If you would like to save variables in separate
-    files, set `filename` None; if you would like to save all variables in a
-    single file, use `filename` to specify the file name.
+    files, set :code:`filename` None; if you would like to save all variables in a
+    single file, use :code:`filename` to specify the file name.
 
     Args:
         executor(Executor): The executor to run for saving persistable variables.
-        dirname(str): The directory path.
-        main_program(Program|None): The program whose persistbale variables will
-                                    be saved. If it is None, the default main
-                                    program will be used automatically.
-                                    Default: None
-        filename(str|None): The file to saved all variables. If you prefer to
-                            save variables in differnet files, set it to None.
-                            Default: None
+                            You can refer to :ref:`api_guide_executor_en` for 
+                            more details.
+        dirname(str): The saving directory path.
+        main_program(Program, optional): The program whose persistbale variables will
+                                         be saved. You can refer to 
+                                         :ref:`api_guide_Program_en` for more details.
+                                         If it is None, the default main program will 
+                                         be used.
+                                         Default: None.
+        filename(str, optional): The file to save all variables. If you prefer to
+                                 save variables in different files, set it to None.
+                                 Default: None.
 
     Returns:
         None
@@ -519,12 +542,21 @@ def save_persistables(executor, dirname, main_program=None, filename=None):
 
             import paddle.fluid as fluid
         
+            dir_path = "./my_paddle_model"
+            file_name = "persistables"
+            image = fluid.data(name='img', shape=[None, 28, 28], dtype='float32')
+            label = fluid.data(name='label', shape=[None, 1], dtype='int64')
+            feeder = fluid.DataFeeder(feed_list=[image, label], place=fluid.CPUPlace())
+           
+            predict = fluid.layers.fc(input=image, size=10, act='softmax')
+            loss = fluid.layers.cross_entropy(input=predict, label=label)
+            avg_loss = fluid.layers.mean(loss)
             exe = fluid.Executor(fluid.CPUPlace())
-            param_path = "./my_paddle_model"
-            # `prog` can be a program defined by the user
-            prog = fluid.default_main_program()
-            fluid.io.save_persistables(executor=exe, dirname=param_path,
-                                       main_program=prog)
+            exe.run(fluid.default_startup_program())
+            fluid.io.save_persistables(executor=exe, dirname=dir_path, filename=file_name)
+            # The persistables variables weights and bias in the fc layer of the network 
+            # are going to be saved in the same file named "persistables" in the path
+            # "./my_paddle_model"
     """
     if main_program and main_program._is_distributed:
         _save_distributed_persistables(
@@ -973,27 +1005,33 @@ def save_inference_model(dirname,
                          program_only=False):
     """
     Prune the given `main_program` to build a new program especially for inference,
-    and then save it and all related parameters to given `dirname` by the `executor`.
+    and then save it and all related parameters to given `dirname` .
     If you just want to save parameters of your trained model, please use the
-    `save_params` API. You can refer to :ref:`api_guide_model_save_reader_en` for
-    more details.
+    :ref:`api_fluid_io_save_params` . You can refer to :ref:`api_guide_model_save_reader_en`
+    for more details.
 
+    Note:
+        The :code:`dirname` is used to specify the folder where inference model 
+        structure and parameters are going to be saved. If you would like to save params of
+        Program in separate files, set `params_filename` None; if you would like to save all 
+        params of Program in a single file, use `params_filename` to specify the file name.
 
     Args:
         dirname(str): The directory path to save the inference model.
-        feeded_var_names(list[str]): Names of variables that need to be feeded data
-                                     during inference.
-        target_vars(list[Variable]): Variables from which we can get inference
-                                     results.
-        executor(Executor): The executor that saves the inference model.
-        main_program(Program|None): The original program, which will be pruned to
+        feeded_var_names(list[str]): list of string. Names of variables that need to be feeded
+                                     data during inference.
+        target_vars(list[Variable]): list of Variable. Variables from which we can get 
+                                     inference results.
+        executor(Executor): The executor that saves the inference model. You can refer 
+                            to :ref:`api_guide_executor_en` for more details.
+        main_program(Program, optional): The original program, which will be pruned to
                                          build the inference model. If is setted None,
-                                    the default main program will be used.
+                                         the global default :code:`_main_program_` will be used.
                                          Default: None.
-        model_filename(str|None): The name of file to save the inference program
+        model_filename(str, optional): The name of file to save the inference program
                                        itself. If is setted None, a default filename
-                                  `__model__` will be used.
-        params_filename(str|None): The name of file to save all related parameters.
+                                       :code:`__model__` will be used.
+        params_filename(str, optional): The name of file to save all related parameters.
                                         If it is setted None, parameters will be saved
                                         in separate files .
         export_for_deployment(bool): If True, programs are modified to only support
@@ -1001,14 +1039,20 @@ def save_inference_model(dirname,
                                      more information will be stored for flexible
                                      optimization and re-training. Currently, only
                                      True is supported.
-        program_only(bool): If True, It will save inference program only, and do not save params of Program.
+                                     Default: True.
+        program_only(bool, optional): If True, It will save inference program only, and do not 
+                                      save params of Program.
+                                      Default: False.
 
     Returns:
-        target_var_name_list(list): The fetch variables' name list
+        The fetch variables' name list
+
+     Return Type:
+        list
 
     Raises:
-        ValueError: If `feed_var_names` is not a list of basestring.
-        ValueError: If `target_vars` is not a list of Variable.
+        ValueError: If `feed_var_names` is not a list of basestring, an exception is thrown.
+        ValueError: If `target_vars` is not a list of Variable, an exception is thrown.
 
     Examples:
         .. code-block:: python
@@ -1018,8 +1062,8 @@ def save_inference_model(dirname,
             path = "./infer_model"
 
             # User defined network, here a softmax regresssion example
-            image = fluid.layers.data(name='img', shape=[1, 28, 28], dtype='float32')
-            label = fluid.layers.data(name='label', shape=[1], dtype='int64')
+            image = fluid.data(name='img', shape=[None, 28, 28], dtype='float32')
+            label = fluid.data(name='label', shape=[None, 1], dtype='int64')
             feeder = fluid.DataFeeder(feed_list=[image, label], place=fluid.CPUPlace())
             predict = fluid.layers.fc(input=image, size=10, act='softmax')
 
@@ -1037,9 +1081,9 @@ def save_inference_model(dirname,
                                           target_vars=[predict],
                                           executor=exe)
 
-            # In this example, the function will prune the default main program
-            # to make it suitable for infering the `predict` var. The pruned
-            # inference program is going to be saved in the "./infer_model/__model__"
+            # In this example, the save_inference_mode inference will prune the default
+            # main program according to the network's input node (img) and output node(predict). 
+            # The pruned inference program is going to be saved in the "./infer_model/__model__"
             # and parameters are going to be saved in separate files under folder
             # "./infer_model".
 

python/paddle/fluid/layers/io.py

@@ -47,25 +47,25 @@ def data(name,
     """
     **Data Layer**
 
-    This function takes in the input and based on whether data has
-    to be returned back as a minibatch, it creates the global variable by using
-    the helper functions. The global variables can be accessed by all the
-    following operators in the graph.
+    This operator creates the global variable. The global variables can be
+    accessed by all the following operators in the graph.
 
-    All the input variables of this function are passed in as local variables
-    to the LayerHelper constructor.
+    Note: 
+        :code:`paddle.fluid.layers.data` is deprecated as it will be removed in 
+        a later version. Please use :code:`paddle.fluid.data` .
 
-    Notice that paddle would only use :code:`shape` to infer the shapes of 
-    following variables in the network during compile-time. During run-time, 
-    paddle would not check whether the shape of the feeded data matches the 
-    :code:`shape` settings in this function. 
+        The :code:`paddle.fluid.layers.data` set shape and dtype at compile time
+        but does NOT check the shape or the dtype of feeded data, this
+        :code:`paddle.fluid.data` checks the shape and the dtype of data feeded 
+        by Executor or ParallelExecutor during run time.
 
     Args:
-       name(str): The name/alias of the function
+       name(str): The name/alias of the variable, see :ref:`api_guide_Name`
+            for more details.
        shape(list): Tuple declaring the shape. If :code:`append_batch_size` is 
             True and there is no -1 inside :code:`shape`, it should be 
-                    considered as the shape of the each sample. Otherwise, it
-                    should be considered as the shape of the batched data.  
+            considered as the shape of the each sample. Otherwise, it should
+            be considered as the shape of the batched data.  
        append_batch_size(bool):
           1. If true, it prepends -1 to the shape.
             For example if shape=[1], the resulting shape is [-1, 1]. This will 
@@ -74,13 +74,20 @@ def data(name,
             append_batch_size will be enforced to be be False (ineffective)
             because PaddlePaddle cannot set more than 1 unknown number on the
             shape.
-       dtype(np.dtype|VarType|str): The type of data : float32, float16, int etc
-       type(VarType): The output type. By default it is LOD_TENSOR.
+       dtype(np.dtype|VarType|str): The type of the data. Supported dtype: bool,
+            float16, float32, float64, int8, int16, int32, int64, uint8.
+       type(VarType): The output type. Supported dtype: VarType.LOD_TENSOR,
+            VarType.SELECTED_ROWS, VarType.NCCL_ID. Default: VarType.LOD_TENSOR. 
        lod_level(int): The LoD Level. 0 means the input data is not a sequence.
+            Default: 0.
        stop_gradient(bool): A boolean that mentions whether gradient should flow.
+            Default: True. 
 
     Returns:
-        Variable: The global variable that gives access to the data.
+        The global variable that gives access to the data.
+
+    Return Type:
+        Variable
 
     Examples:
         .. code-block:: python
@@ -531,29 +538,43 @@ def py_reader(capacity,
     """
     Create a Python reader for data feeding in Python
 
-    This layer returns a Reader Variable.
+    This operator returns a Reader Variable.
     The Reader provides :code:`decorate_paddle_reader()` and
     :code:`decorate_tensor_provider()` to set a Python generator as the data
-    source. More details :ref:`user_guide_use_py_reader_en` .  When
-    :code:`Executor::Run()` is invoked in C++ side, the data from the generator
-    would be read automatically. Unlike :code:`DataFeeder.feed()`, the data
-    reading process and :code:`Executor::Run()` process can run in parallel
-    using :code:`py_reader`. The :code:`start()` method of the Reader should be
-    called when each pass begins, while the :code:`reset()` method should be
-    called when the pass ends and :code:`fluid.core.EOFException` raises.
-    Note that :code:`Program.clone()` method cannot clone :code:`py_reader`.
+    source and feed the data from the data source to the Reader Variable. 
+    When :code:`Executor::Run()` is invoked in C++ side, the data from the 
+    generator would be read automatically. Unlike :code:`DataFeeder.feed()`,
+    the data reading process and :code:`Executor::Run()` process can run in 
+    parallel using :code:`py_reader`. The :code:`start()` method of the Reader
+    should be called when each pass begins, while the :code:`reset()` method 
+    should be called when the pass ends and :code:`fluid.core.EOFException` raises.
+
+    Note:
+       :code:`Program.clone()` method cannot clone :code:`py_reader`. You can 
+       refer to :ref:`api_fluid_Program` for more details.
+       
+       The :code:`read_file` call needs to be in the program block of :code:`py_reader`.
+       You can refer to :ref:`api_fluid_layers_read_file` for more details.
 
     Args:
        capacity(int): The buffer capacity maintained by :code:`py_reader`.
-       shapes(list|tuple): List of tuples which declaring data shapes.
-       dtypes(list|tuple): List of strs which declaring data type.
+       shapes(list|tuple): List of tuples which declaring data shapes. shapes[i] 
+            represents the i-th data shape.
+       dtypes(list|tuple): List of strings which declaring data type. Supported dtype:
+            bool, float16, float32, float64, int8, int16, int32, int64, uint8.
        lod_levels(list|tuple): List of ints which declaring data lod_level.
-       name(basestring): The prefix Python queue name and Reader name. None will
-            be generated automatically.
-       use_double_buffer(bool): Whether use double buffer or not.
+       name(basestring): The default value is None. Normally there is no
+            need for user to set this property. For more information, please
+            refer to :ref:`api_guide_Name`.
+       use_double_buffer(bool): Whether use double buffer or not. The double buffer is 
+            for pre-reading the data of the next batch and copy the data asynchronously 
+            from CPU to GPU. Default is True.
 
     Returns:
-       Variable: A Reader from which we can get feeding data.
+       A Reader from which we can get feeding data.
+
+    Return Type:
+       Variable
 
     Examples:
        1. The basic usage of :code:`py_reader` is as follows:

python/paddle/fluid/reader.py

@@ -595,7 +595,10 @@ class PyReader(DataLoaderBase):
             use return_list=True in dygraph mode. 
 
     Returns:
-        reader (Reader): the created reader object.
+        the created reader object.
+
+    Return type:
+        reader(Reader)
 
     Examples:
         1. If iterable = False, the created PyReader object is almost the
@@ -616,6 +619,11 @@ class PyReader(DataLoaderBase):
            ITER_NUM = 5
            BATCH_SIZE = 3
            
+           def network(image, label):
+               # User-defined network, here is an example of softmax regression.
+               predict = fluid.layers.fc(input=image, size=10, act='softmax')           
+               return fluid.layers.cross_entropy(input=predict, label=label)
+
            def reader_creator_random_image_and_label(height, width):
                def reader():
                    for i in range(ITER_NUM):
@@ -626,8 +634,8 @@ class PyReader(DataLoaderBase):
                        yield fake_image, fake_label
                return reader
 
-           image = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
-           label = fluid.layers.data(name='label', shape=[1], dtype='int64')
+           image = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
+           label = fluid.data(name='label', shape=[None, 1], dtype='int64')
 
            reader = fluid.io.PyReader(feed_list=[image, label],
                                       capacity=4,
@@ -636,8 +644,8 @@ class PyReader(DataLoaderBase):
            user_defined_reader = reader_creator_random_image_and_label(784, 784)
            reader.decorate_sample_list_generator(
                paddle.batch(user_defined_reader, batch_size=BATCH_SIZE))
-           # definition of network is omitted
-           executor = fluid.Executor(fluid.CUDAPlace(0))
+           loss = network(image, label)
+           executor = fluid.Executor(fluid.CPUPlace())
            executor.run(fluid.default_startup_program())
            for i in range(EPOCH_NUM):
                reader.start()
@@ -665,26 +673,35 @@ class PyReader(DataLoaderBase):
            ITER_NUM = 5
            BATCH_SIZE = 10
 
+           def network(image, label):
+               # User-defined network, here is an example of softmax regression.
+               predict = fluid.layers.fc(input=image, size=10, act='softmax')           
+               return fluid.layers.cross_entropy(input=predict, label=label)
+
            def reader_creator_random_image(height, width):
                def reader():
                    for i in range(ITER_NUM):
-                       yield np.random.uniform(low=0, high=255, size=[height, width]),
+                       fake_image = np.random.uniform(low=0, high=255, size=[height, width])
+                       fake_label = np.ones([1])
+                       yield fake_image, fake_label 
                return reader
 
-           image = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
-           reader = fluid.io.PyReader(feed_list=[image], capacity=4, iterable=True, return_list=False)
+           image = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
+           label = fluid.data(name='label', shape=[None, 1], dtype='int64')
+           reader = fluid.io.PyReader(feed_list=[image, label], capacity=4, iterable=True, return_list=False)
 
            user_defined_reader = reader_creator_random_image(784, 784)
            reader.decorate_sample_list_generator(
                paddle.batch(user_defined_reader, batch_size=BATCH_SIZE),
-               fluid.core.CUDAPlace(0))
-           # definition of network is omitted
-           executor = fluid.Executor(fluid.CUDAPlace(0))
-           executor.run(fluid.default_main_program())
+                   fluid.core.CPUPlace())
+           
+           loss = network(image, label)
+           executor = fluid.Executor(fluid.CPUPlace())
+           executor.run(fluid.default_startup_program())
            
            for _ in range(EPOCH_NUM):
                for data in reader():
-                   executor.run(feed=data)
+                   executor.run(feed=data, fetch_list=[loss])
 
 
         3. If return_list=True, the return values would be presented as list instead of dict. 
@@ -758,12 +775,12 @@ class PyReader(DataLoaderBase):
                     for i in range(5):
                         yield np.random.uniform(low=0, high=255, size=[784, 784]),
 
-                image = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
+                image = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
                 reader = fluid.io.PyReader(feed_list=[image], capacity=4, iterable=False)
                 reader.decorate_sample_list_generator(
                     paddle.batch(generator, batch_size=BATCH_SIZE))
 
-                executor = fluid.Executor(fluid.CUDAPlace(0))
+                executor = fluid.Executor(fluid.CPUPlace())
                 executor.run(fluid.default_startup_program())
                 for i in range(3):
                     reader.start()
@@ -795,12 +812,12 @@ class PyReader(DataLoaderBase):
                     for i in range(5):
                         yield np.random.uniform(low=0, high=255, size=[784, 784]),
 
-                image = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
+                image = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
                 reader = fluid.io.PyReader(feed_list=[image], capacity=4, iterable=False)
                 reader.decorate_sample_list_generator(
                     paddle.batch(generator, batch_size=BATCH_SIZE))
 
-                executor = fluid.Executor(fluid.CUDAPlace(0))
+                executor = fluid.Executor(fluid.CPUPlace())
                 executor.run(fluid.default_startup_program())
                 for i in range(3):
                     reader.start()
@@ -849,6 +866,11 @@ class PyReader(DataLoaderBase):
                 ITER_NUM = 15
                 BATCH_SIZE = 3
         
+                def network(image, label):
+                    # User-defined network, here is an example of softmax regression.
+                    predict = fluid.layers.fc(input=image, size=10, act='softmax')           
+                    return fluid.layers.cross_entropy(input=predict, label=label)
+
                 def random_image_and_label_generator(height, width):
                     def generator():
                         for i in range(ITER_NUM):
@@ -859,21 +881,21 @@ class PyReader(DataLoaderBase):
                             yield fake_image, fake_label
                     return generator
 
-                image = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
-                label = fluid.layers.data(name='label', shape=[1], dtype='int32')
+                image = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
+                label = fluid.data(name='label', shape=[None, 1], dtype='int64')
                 reader = fluid.io.PyReader(feed_list=[image, label], capacity=4, iterable=True)
 
                 user_defined_generator = random_image_and_label_generator(784, 784)
                 reader.decorate_sample_generator(user_defined_generator,
                                                  batch_size=BATCH_SIZE,
-                                                 places=[fluid.CUDAPlace(0)])
-                # definition of network is omitted
-                executor = fluid.Executor(fluid.CUDAPlace(0))
-                executor.run(fluid.default_main_program())
+                                                 places=[fluid.CPUPlace()])
+                loss = network(image, label)
+                executor = fluid.Executor(fluid.CPUPlace())
+                executor.run(fluid.default_startup_program())
 
                 for _ in range(EPOCH_NUM):
                     for data in reader():
-                        executor.run(feed=data)
+                        executor.run(feed=data, fetch_list=[loss])
     
         '''
         self._loader.set_sample_generator(sample_generator, batch_size,
@@ -905,6 +927,11 @@ class PyReader(DataLoaderBase):
                 ITER_NUM = 15
                 BATCH_SIZE = 3
 
+                def network(image, label):
+                    # User-defined network, here is an example of softmax regression.
+                    predict = fluid.layers.fc(input=image, size=10, act='softmax')           
+                    return fluid.layers.cross_entropy(input=predict, label=label)
+
                 def random_image_and_label_generator(height, width):
                     def generator():
                         for i in range(ITER_NUM):
@@ -915,21 +942,22 @@ class PyReader(DataLoaderBase):
                             yield fake_image, fake_label
                     return generator
 
-                image = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
-                label = fluid.layers.data(name='label', shape=[1], dtype='int32')
+                image = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
+                label = fluid.data(name='label', shape=[None, 1], dtype='int64')
                 reader = fluid.io.PyReader(feed_list=[image, label], capacity=4, iterable=True)
 
                 user_defined_generator = random_image_and_label_generator(784, 784)
                 reader.decorate_sample_list_generator(
                     paddle.batch(user_defined_generator, batch_size=BATCH_SIZE),
-                    fluid.core.CUDAPlace(0))
-                # definition of network is omitted
-                executor = fluid.Executor(fluid.core.CUDAPlace(0))
-                executor.run(fluid.default_main_program())
+                    fluid.core.CPUPlace())
+                
+                loss = network(image, label)
+                executor = fluid.Executor(fluid.core.CPUPlace())
+                executor.run(fluid.default_startup_program())
 
                 for _ in range(EPOCH_NUM):
                     for data in reader():
-                        executor.run(feed=data)
+                        executor.run(feed=data, fetch_list=[loss])
                  
         '''
         self._loader.set_sample_list_generator(reader, places)
@@ -959,6 +987,11 @@ class PyReader(DataLoaderBase):
                 ITER_NUM = 15
                 BATCH_SIZE = 3
                
+                def network(image, label):
+                    # User-defined network, here is an example of softmax regression.
+                    predict = fluid.layers.fc(input=image, size=10, act='softmax')           
+                    return fluid.layers.cross_entropy(input=predict, label=label)
+
                 def random_image_and_label_generator(height, width):
                     def generator():
                         for i in range(ITER_NUM):
@@ -966,22 +999,25 @@ class PyReader(DataLoaderBase):
                                                             high=255,
                                                             size=[BATCH_SIZE, height, width])
                             batch_label = np.ones([BATCH_SIZE, 1])
+                            batch_image = batch_image.astype('float32')
+                            batch_label = batch_label.astype('int64')
                             yield batch_image, batch_label
                     return generator
 
-                image = fluid.layers.data(name='image', shape=[784, 784], dtype='float32')
-                label = fluid.layers.data(name='label', shape=[1], dtype='int32')
+                image = fluid.data(name='image', shape=[None, 784, 784], dtype='float32')
+                label = fluid.data(name='label', shape=[None, 1], dtype='int64')
                 reader = fluid.io.PyReader(feed_list=[image, label], capacity=4, iterable=True)
 
                 user_defined_generator = random_image_and_label_generator(784, 784)
-                reader.decorate_batch_generator(user_defined_generator, fluid.CUDAPlace(0))
-                # definition of network is omitted
-                executor = fluid.Executor(fluid.CUDAPlace(0))
-                executor.run(fluid.default_main_program())
+                reader.decorate_batch_generator(user_defined_generator, fluid.CPUPlace())
+                
+                loss = network(image, label)
+                executor = fluid.Executor(fluid.CPUPlace())
+                executor.run(fluid.default_startup_program())
 
                 for _ in range(EPOCH_NUM):
                     for data in reader():
-                        executor.run(feed=data)
+                        executor.run(feed=data, fetch_list=[loss])
 
         '''
         self._loader.set_batch_generator(reader, places)