Merge pull request PaddlePaddle#2067 from reyoung/feature/expose_inference_in_py_api

Expose Inference in Python V2 API.

Author: lcy-seso

python/paddle/v2/inference.py

@@ -5,15 +5,22 @@
 import minibatch
 from data_feeder import DataFeeder
 
-__all__ = ['infer']
+__all__ = ['infer', 'Inference']
 
 
 class Inference(object):
  """
  Inference combines neural network output and parameters together
  to do inference.
+ 
+ .. code-block:: python
+ 
+ inferer = Inference(output_layer=prediction, parameters=parameters)
+ for data_batch in batches:
+ print inferer.infer(data_batch)
+
 
- :param outptut_layer: The neural network that should be inferenced.
+ :param output_layer: The neural network that should be inferenced.
  :type output_layer: paddle.v2.config_base.Layer or the sequence
  of paddle.v2.config_base.Layer
  :param parameters: The parameters dictionary.
@@ -56,8 +63,14 @@ def iter_infer_field(self, field, **kwargs):
  item = [each_result[each_field] for each_field in field]
  yield item
 
- def infer(self, field='value', **kwargs):
+ def infer(self, input, field='value', **kwargs):
+ """
+ Infer a data by model.
+ :param input: input data batch. Should be python iterable object.
+ :param field: output field.
+ """
  retv = None
+ kwargs['input'] = input
  for result in self.iter_infer_field(field=field, **kwargs):
  if retv is None:
  retv = [[] for i in xrange(len(result))]
@@ -79,7 +92,7 @@ def infer(output_layer, parameters, input, feeding=None, field='value'):
 
  .. code-block:: python
 
- result = paddle.infer(outptut_layer=prediction, 
+ result = paddle.infer(output_layer=prediction, 
  parameters=parameters, 
  input=SomeData)
  print result