Remove scope hack

1. weights are bound to respective models
2. models can coexists in same scope (actual parameter names are uniqued)
3. this make model composition (e.g., transfer learning) harder

model.py

@@ -68,10 +68,6 @@ class StaticGraphAdapter(object):
         self._startup_prog = fluid.default_startup_program()
         self._main_prog = fluid.default_main_program()
 
-        # HACK separate models by cleanup global scope
-        self._scope = fluid.executor.global_scope()
-        fluid.executor.g_scope = fluid.core.Scope()
-
         self._label_vars = None  # label variables
         self._endpoints = {}
         self._loss_endpoint = None
@@ -118,13 +114,11 @@ class StaticGraphAdapter(object):
         if prog is None or self.model._optimizer is None:
             print("optimizer not initialized, save parameters only")
             prog = self._main_prog
-        with fluid.executor.scope_guard(self._scope):
-            fluid.save(prog, path)
+        fluid.save(prog, path)
 
     def load(self, path):
         prog = self._main_prog
-        with fluid.executor.scope_guard(self._scope):
-            fluid.load(prog, path, self._executor)
+        fluid.load(prog, path, self._executor)
 
     def _run(self, inputs, labels=None, device='CPU', device_ids=None):
         inputs = to_list(inputs)
@@ -133,18 +127,17 @@ class StaticGraphAdapter(object):
         assert len(inputs) == len(self._input_desc), "number of inputs" \
             + " does not match number of arguments of `forward` method"
 
-        with fluid.executor.scope_guard(self._scope):
-            if self._progs.get(self.mode, None) is None:
-                self._make_program(self._infer_input_vars(inputs))
+        if self._progs.get(self.mode, None) is None:
+            self._make_program(self._infer_input_vars(inputs))
 
-            ids = [str(i) for i in device_ids]
-            ids.sort()
-            prog_hash = '_'.join([self.mode] + ids)
-            compiled_prog = self._compiled_progs.get(prog_hash, None)
-            if compiled_prog is None:
-                compiled_prog = self._compile_and_initialize(
-                    self._progs[self.mode], device, device_ids)
-                self._compiled_progs[prog_hash] = compiled_prog
+        ids = [str(i) for i in device_ids]
+        ids.sort()
+        prog_hash = '_'.join([self.mode] + ids)
+        compiled_prog = self._compiled_progs.get(prog_hash, None)
+        if compiled_prog is None:
+            compiled_prog = self._compile_and_initialize(
+                self._progs[self.mode], device, device_ids)
+            self._compiled_progs[prog_hash] = compiled_prog
 
         feed = {}
         input_names = [name for name in self._input_desc.keys()]
@@ -157,7 +150,7 @@ class StaticGraphAdapter(object):
                 feed[v.name] = labels[idx]
 
         outputs = self._executor.run(
-            compiled_prog, scope=self._scope, feed=feed,
+            compiled_prog, feed=feed,
             fetch_list=self._endpoints[self.mode])
         return outputs