Make Scope can lookup variable name by variable

* Refine unittest also

paddle/framework/scope.h

@@ -56,7 +56,9 @@ class Scope {
     if (var) {
       return var;
     } else {
-      vars_[name] = std::unique_ptr<Variable>(new Variable());
+      auto ptr = new Variable();
+      vars_[name] = std::unique_ptr<Variable>(ptr);
+      var_names_[ptr] = name;
       return GetVariable(name);
     }
   }
@@ -88,7 +90,16 @@ class Scope {
             (parent_ && parent_->HasVariable(name)));
   }
 
+  std::string GetVariableName(Variable* const var) const {
+    try {
+      return var_names_.at(var);
+    } catch (...) {
+      return "";
+    }
+  }
+
  private:
+  std::unordered_map<Variable*, std::string> var_names_;
   std::unordered_map<std::string, std::unique_ptr<Variable>> vars_;
   std::shared_ptr<Scope> parent_{nullptr};
 };

paddle/framework/scope_test.cc

@@ -40,6 +40,8 @@ TEST(Scope, Create) {
   /// already exist.
   Variable* var4 = scope->CreateVariable("a");
   EXPECT_EQ(var4, var2);
+
+  EXPECT_EQ("a", scope->GetVariableName(var4));
 }
 
 TEST(Scope, Parent) {

paddle/pybind/pybind.cc

@@ -56,6 +56,11 @@ void ExposeOperator(ClassType& m) {
       .def("__str__", &ClassType::type::DebugString);
 }
 
+static size_t UniqueIntegerGenerator() {
+  static std::atomic<size_t> generator;
+  return generator.fetch_add(1);
+}
+
 PYBIND11_PLUGIN(core) {
   py::module m("core", "C++ core of PaddlePaddle");
 
@@ -106,7 +111,8 @@ All parameter, weight, gradient are variables in Paddle.
            py::return_value_policy::reference)
       .def("create_var",
            &pd::Scope::CreateVariable,
-           py::return_value_policy::reference);
+           py::return_value_policy::reference)
+      .def("get_var_name", &pd::Scope::GetVariableName);
 
   //! @note: Be careful! PyBind will return std::string as an unicode, not
   //! Python str. If you want a str object, you should cast them in Python.
@@ -166,5 +172,7 @@ All parameter, weight, gradient are variables in Paddle.
       .def("complete_add_op", [](PlainNetPtr& self) { self->CompleteAddOp(); });
   ExposeOperator(net);
 
+  m.def("unique_integer", UniqueIntegerGenerator);
+
   return m.ptr();
 }

python/paddle/v2/framework/network.py

@@ -29,35 +29,31 @@ class NetworkFunctor(object):
             if ipt in kwargs:
                 var = kwargs[ipt]
                 if isinstance(var, basestring):
-                    var_name = var
                     var = create_var(var)
-                    self.net.var_name_map[var] = var_name
                 if not isinstance(var, core.Variable):
                     raise TypeError(
                         "Input of op creation must be string or variable")
 
-                kwargs[ipt] = self.net.var_name_map[var]
+                kwargs[ipt] = get_cur_scope().get_var_name(var)
 
         notemp_outputs = self.func.all_not_temp_output_args
 
         for name in notemp_outputs:
             if name not in kwargs:
                 kwargs[
-                    name] = self.func.__name__ + "@OUT@%d" % self.net.generate_idx
-                self.net.generate_idx += 1
+                    name] = self.func.__name__ + "@OUT@%d" % core.unique_integer(
+                    )
 
         outputs = self.func.all_output_args
         for opt in outputs:
             if opt in kwargs:
                 var = kwargs[opt]
                 if isinstance(var, basestring):
-                    var_name = var
                     var = create_var(var)
-                    self.net.var_name_map[var] = var_name
                 if not isinstance(var, core.Variable):
                     raise TypeError(
                         "Output of op creation must be string or variable")
-                kwargs[opt] = self.net.var_name_map[var]
+                kwargs[opt] = get_cur_scope().get_var_name(var)
 
         op = self.func(**kwargs)
 
@@ -93,8 +89,6 @@ class Network(object):
         self.net = core.Net.create()
         funcs = (func_name for func_name in dir(op_creations)
                  if not func_name.startswith("__"))
-        self.generate_idx = 0
-        self.var_name_map = dict()
 
         # TODO(yuyang18): This code can work, but do not generate a good
         # docstring, try to give a better way generate function in runtime

python/paddle/v2/framework/tests/test_network.py

@@ -18,6 +18,15 @@ class TestNet(unittest.TestCase):
         Op(sigmoid), inputs:(@TEMP@fc@0), outputs:(fc@OUT@1).
 ''', str(net))
 
+        net2 = Network()
+        tmp = net2.add_two(X="X", Y="Y")
+        self.assertTrue(isinstance(tmp, core.Variable))
+        net2.complete_add_op()
+        self.assertEqual(
+            '''Op(naive_net), inputs:(X, Y), outputs:(add_two@OUT@2).
+    Op(add_two), inputs:(X, Y), outputs:(add_two@OUT@2).
+''', str(net2))
+
 
 if __name__ == '__main__':
     unittest.main()