add example for adamoptimizer

fix API.spec
test=develop

Author: wopeizl

paddle/fluid/API.spec

@@ -251,8 +251,8 @@ paddle.fluid.layers.Preprocessor.inputs (ArgSpec(args=['self'], varargs=None, ke
 paddle.fluid.layers.Preprocessor.outputs (ArgSpec(args=['self'], varargs='outs', keywords=None, defaults=None), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
 paddle.fluid.layers.load (ArgSpec(args=['out', 'file_path', 'load_as_fp16'], varargs=None, keywords=None, defaults=(None,)), ('document', '9d1a4bc97bbce9fa1d4f7a4200a771ff'))
 paddle.fluid.layers.create_tensor (ArgSpec(args=['dtype', 'name', 'persistable'], varargs=None, keywords=None, defaults=(None, False)), ('document', 'c0c3d0194f83fff8ea99ce0820657dae'))
-paddle.fluid.layers.create_parameter (ArgSpec(args=['shape', 'dtype', 'name', 'attr', 'is_bias', 'default_initializer'], varargs=None, keywords=None, defaults=(None, None, False, None)), ('document', 'd62b866c899bc1fedb5385f95b88e1f8'))
-paddle.fluid.layers.create_global_var (ArgSpec(args=['shape', 'value', 'dtype', 'persistable', 'force_cpu', 'name'], varargs=None, keywords=None, defaults=(False, False, None)), ('document', 'ab914fac893607e29ac6e52bbdbea1a4'))
+paddle.fluid.layers.create_parameter (ArgSpec(args=['shape', 'dtype', 'name', 'attr', 'is_bias', 'default_initializer'], varargs=None, keywords=None, defaults=(None, None, False, None)), ('document', 'b6fe28cffff32d15e45c411bcf815cb7'))
+paddle.fluid.layers.create_global_var (ArgSpec(args=['shape', 'value', 'dtype', 'persistable', 'force_cpu', 'name'], varargs=None, keywords=None, defaults=(False, False, None)), ('document', '90eb79e0d1261ec2bac7c775ee4f459b'))
 paddle.fluid.layers.cast (ArgSpec(args=['x', 'dtype'], varargs=None, keywords=None, defaults=None), ('document', '992eb42590fc1c380841a6db72ce78b3'))
 paddle.fluid.layers.tensor_array_to_tensor (ArgSpec(args=['input', 'axis', 'name'], varargs=None, keywords=None, defaults=(1, None)), ('document', 'b12717d3d4567e6119589f7f655b0cbb'))
 paddle.fluid.layers.concat (ArgSpec(args=['input', 'axis', 'name'], varargs=None, keywords=None, defaults=(0, None)), ('document', 'f9e905b48123914c78055a45fe23106a'))

python/paddle/fluid/optimizer.py

@@ -1152,8 +1152,30 @@ class AdamOptimizer(Optimizer):
     Examples:
         .. code-block:: python
 
-            optimizer = fluid.optimizer.Adam(learning_rate=0.2)
-            optimizer.minimize(cost)
+            import paddle
+            import paddle.fluid as fluid
+
+            place = fluid.CPUPlace()
+            main = fluid.Program()
+            with fluid.program_guard(main):
+                x = fluid.layers.data(name='x', shape=[13], dtype='float32')
+                y = fluid.layers.data(name='y', shape=[1], dtype='float32')
+                y_predict = fluid.layers.fc(input=x, size=1, act=None)
+                cost = fluid.layers.square_error_cost(input=y_predict, label=y)
+                avg_cost = fluid.layers.mean(cost)
+
+                adam_optimizer = fluid.optimizer.AdamOptimizer(0.01)
+                adam_optimizer.minimize(avg_cost)
+
+                fetch_list = [avg_cost]
+                train_reader = paddle.batch(
+                    paddle.dataset.uci_housing.train(), batch_size=1)
+                feeder = fluid.DataFeeder(place=place, feed_list=[x, y])
+                exe = fluid.Executor(place)
+                exe.run(fluid.default_startup_program())
+                for data in train_reader():
+                    exe.run(main, feed=feeder.feed(data), fetch_list=fetch_list)
+                    break
 
     """
     _moment1_acc_str = "moment1"