By default is all reduce

paddle/fluid/framework/details/build_strategy.h

@@ -27,7 +27,7 @@ struct BuildStrategy {
     kCustomized = 2,
   };
 
-  ReduceStrategy reduce_{ReduceStrategy::kReduce};
+  ReduceStrategy reduce_{ReduceStrategy::kAllReduce};
   GradientScaleStrategy gradient_scale_{GradientScaleStrategy::kCoeffNumDevice};
 };
 

paddle/fluid/framework/details/fetch_op_handle.cc

@@ -44,12 +44,6 @@ void FetchOpHandle::WaitAndMergeCPUTensors() const {
   data_->at(offset_).MergeLoDTensor(tensors_ptr, platform::CPUPlace());
 }
 
-template <typename T, typename... ARGS>
-inline T &Ref(T *ptr, ARGS &&... args) {
-  PADDLE_ENFORCE(ptr != nullptr, args...);
-  return *ptr;
-}
-
 void FetchOpHandle::RunImpl() {
   WaitInputVarGenerated(platform::CPUPlace());
 
@@ -59,14 +53,10 @@ void FetchOpHandle::RunImpl() {
   platform::CPUPlace cpu;
   auto &scopes = *local_scopes_;
 
-  PADDLE_ENFORCE_EQ(inputs_.size(), scopes.size());
   for (size_t i = 0; i < scopes.size(); ++i) {
     auto &scope = scopes[i];
-    auto *var = Ref(Ref(scope->FindVar(kLocalExecScopeName), "Cannot find %s",
-                        kLocalExecScopeName)
-                        .Get<Scope *>(),
-                    "Cannot get scope")
-                    .FindVar(var_name);
+    auto *var =
+        scope->FindVar(kLocalExecScopeName)->Get<Scope *>()->FindVar(var_name);
     PADDLE_ENFORCE_NOT_NULL(var, "Cannot find variable %s in execution scope",
                             var_name);
     auto &t = var->Get<framework::LoDTensor>();