Created by: Xreki

Suggested by @qingqing01 , we may implement another Run() in paddle/framework/executor.h which do the same things as the Run() of Python Executor.

https://github.com/PaddlePaddle/Paddle/blob/144854d2e86efce8858b34518c1ee5f4b48d9407/python/paddle/v2/fluid/executor.py#L125-L132

The interface maybe like and will do following things:

void Run(const ProgramDesc& program,
         Scope* scope,
         std::map<std::string, Tensor>& feeds,
         std::map<std::string, Tensor>& fetchs,
         std::string& feed_var_name="feed",
         std::string& fetch_var_name="fetch") {
  1. clone the program
  2. prepend feed_op
  3. set feed variables
  4. append fetch_op
  5. call Run(const ProgramDesc&, Scope*, int, bool create_local_scope = true, bool create_vars = true)
  6. get fetch variables 
}

So that we can directly Run both in Python API and C++ API.