fix eval mode bug; test=develop (#17499)

python/paddle/fluid/dygraph/tracer.py

@@ -54,9 +54,7 @@ class Tracer(core.Tracer):
         self._trace_id = 0
 
     def trace_op(self, op, inputs, outputs, stop_gradient=False):
-        # TODO(minqiyang): remove this line after we take apart all
-        # backward grads and forward variables
-        if self._train_mode:
+        # TODO(hy): previous version will cause memory failed
         op.inputs = inputs
         inps = defaultdict(list)
         for k, vars in six.iteritems(inputs):
@@ -74,27 +72,6 @@ class Tracer(core.Tracer):
             elif isinstance(vars, list) or isinstance(vars, tuple):
                 for var in vars:
                     outs[k].append(var._ivar)
-        else:
-            inps = defaultdict(list)
-            for k, vars in six.iteritems(inputs):
-                if isinstance(vars, framework.Variable):
-                    op.previous_ops.append(vars.op)
-                    inps[k].append(vars._ivar)
-                elif isinstance(vars, list) or isinstance(vars, tuple):
-                    for var in vars:
-                        op.previous_ops.append(var.op)
-                        inps[k].append(var._ivar)
-
-            op.outputs = outputs
-            outs = defaultdict(list)
-            for k, vars in six.iteritems(outputs):
-                if isinstance(vars, framework.Variable):
-                    vars.op = op
-                    outs[k].append(vars._ivar)
-                elif isinstance(vars, list) or isinstance(vars, tuple):
-                    for var in vars:
-                        var.op = op
-                        outs[k].append(var._ivar)
 
         # record op's trace id
         op.iop._trace_id = self._trace_id

python/paddle/fluid/framework.py

@@ -1670,13 +1670,18 @@ class Block(object):
             Operator: the append Operator.
         """
         if in_dygraph_mode():
+            attrs = kwargs.get("attrs", {})
+            if _dygraph_tracer_._train_mode == False:
+                # eval mode
+                attrs['is_test'] = True
+
             op = Operator(
                 block=self,
                 desc=None,
                 type=kwargs.get("type", None),
                 inputs=None,
                 outputs=None,
-                attrs=kwargs.get("attrs", {}))
+                attrs=attrs)
 
             # record ops in tracer rather than blocks
             #