update based on review

doc/design/executor.md

@@ -20,31 +20,4 @@ It does not do graph partitioning, meaning dividing the `ProgramDesc` into sever
 
 ## Implementation
 
-`Executor` evaluates a `ProgramDesc`. Essentially, it instantiates Variables and Operators, then run all the operators
-
-```c++
-void Executor::Run(const ProgramDesc& pdesc, Scope* scope, int block_id) {
-  auto& block = pdesc.blocks(block_id);
-  auto& device = device_contexts_[0];
-
-  // Instantiate all the vars in the global scope
-  for (auto& var : block.vars()) {
-    scope->NewVar(var.name());
-  }
-
-  // Run the block
-  Scope& local_scope = scope->NewScope();
-  for (auto& op_desc : block.ops()) {
-    for (auto& var : op_desc.outputs()) {
-      for (auto& argu : var.arguments()) {
-        // Create temp variable in the local_scope
-        if (local_scope.FindVar(argu) == nullptr) {
-          local_scope.NewVar(argu);
-        }
-      }
-    }
-    auto op = paddle::framework::OpRegistry::CreateOp(op_desc);
-    op->Run(local_scope, *device);
-  }
-}
-```
+`Executor` evaluates a `ProgramDesc`. Essentially, it instantiates Variables and Operators, then run all the operators in sequence. [[code]](https://github.com/PaddlePaddle/Paddle/blob/develop/paddle/framework/executor.cc)