disable comm fusion in parallel optimizer temp

mindspore/ccsrc/frontend/parallel/step_parallel.cc

@@ -1287,7 +1287,8 @@ void ApplyParallelOptOnParam(TensorLayout *tensor_layout, const OperatorInfoPtr
     auto allgather = cnode->input(index)->cast<CNodePtr>();
     auto prim = GetValueNode<PrimitivePtr>(allgather->input(0));
     auto attrs = prim->attrs();
-    attrs["fusion"] = MakeValue(1);
+    // enable fusion flag later when it's supported in backend
+    attrs["fusion"] = MakeValue(0);
     prim->SetAttrs(attrs);
     MS_LOG(INFO) << "Parallel optimizer is applied on " << parameter->ToString();
   } else {

mindspore/nn/optim/optimizer.py

@@ -151,8 +151,8 @@ class Optimizer(Cell):
         if context.get_auto_parallel_context("enable_parallel_optimizer"):
             if _get_parallel_mode() == ParallelMode.DATA_PARALLEL:
                 self.use_parallel = True
-            elif _get_parallel_mode() == ParallelMode.STAND_ALONE:
-                raise RuntimeError("Parallel optimizer is not supported in stand alone mode.")
+            elif _get_parallel_mode() in (ParallelMode.STAND_ALONE, ParallelMode.HYBRID_PARALLEL):
+                raise RuntimeError("Parallel optimizer is not supported in {}.".format(_get_parallel_mode()))
             else:
                 self.use_parallel = False
         else: