support AMP.use_amp arg

ppcls/engine/engine.py

@@ -525,7 +525,8 @@ class Engine(object):
 
     def _init_amp(self):
         amp_config = self.config.get("AMP", None)
-        use_amp = True if amp_config else False
+        use_amp = True if amp_config and amp_config.get("use_amp",
+                                                        True) else False
 
         if not use_amp:
             self.auto_cast = AutoCast(use_amp)

ppcls/utils/amp.py

@@ -21,7 +21,7 @@ class AutoCast:
                     paddle.amp.auto_cast,
                     level=amp_level,
                     use_promote=use_promote)
-            # paddle version < 2.3.0 and not develop
+            # paddle version <= 2.4.x and not develop
             else:
                 self.cast_context = partial(
                     paddle.amp.auto_cast, level=amp_level)