diff --git a/mindspore/ccsrc/backend/optimizer/somas/somas_node.cc b/mindspore/ccsrc/backend/optimizer/somas/somas_node.cc
deleted file mode 100644
index 532b4fc605..0000000000
--- a/mindspore/ccsrc/backend/optimizer/somas/somas_node.cc
+++ /dev/null
@@ -1,45 +0,0 @@
-/**
- * Copyright 2020 Huawei Technologies Co., Ltd
-
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
-
- * http://www.apache.org/licenses/LICENSE-2.0
-
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
-*/
-
-#include "backend/optimizer/somas/somas_node.h"
-#include <algorithm>
-
-namespace mindspore {
-namespace somas {
-void SomasNode::ComputeAncestorNodes() {
-  // Fast algorithm: assuming nodes execute this function in the received topological order
-  int64_t thisId = this->GetStream()->GetId();
-
-  for (SomasNodePtr node : ancestor_nodes_) {
-    int64_t ancestorId = node->GetStream()->GetId();
-    // Map Improvement for max_ancestor_order
-    if (thisId != ancestorId) {
-      this->anc_stream_max_order_[ancestorId] = std::max(this->anc_stream_max_order_[ancestorId], node->GetId());
-    }
-    for (SomasStreamPtr stream : node->GetStream()->ancestor_streams_) {
-      this->anc_stream_max_order_[stream->GetId()] =
-        std::max(this->anc_stream_max_order_[stream->GetId()], node->anc_stream_max_order_[stream->GetId()]);
-    }
-  }
-}
-
-void SomasNode::PresetAncestorStreams(const std::vector<SomasStreamPtr> stream_vector) {
-  for (SomasStreamPtr stream : stream_vector) {
-    anc_stream_max_order_[stream->GetId()] = 0;
-  }
-}
-}  // namespace somas
-}  // namespace mindspore
diff --git a/mindspore/ccsrc/backend/optimizer/somas/somas_node.h b/mindspore/ccsrc/backend/optimizer/somas/somas_node.h
index 64279fb7b1..fc127a1162 100644
--- a/mindspore/ccsrc/backend/optimizer/somas/somas_node.h
+++ b/mindspore/ccsrc/backend/optimizer/somas/somas_node.h
@@ -66,10 +66,6 @@ class SomasNode {
   SomasStreamPtr GetStream() { return stream_; }
   const NodeType &GetType() { return type_; }
 
-  // Computing ancestors
-  void PresetAncestorStreams(const std::vector<SomasStreamPtr> stream_vector);
-  void ComputeAncestorNodes();
-
  private:
   const size_t id_{0};
   SomasStreamPtr const stream_;
diff --git a/mindspore/ccsrc/backend/optimizer/somas/somas_stream.cc b/mindspore/ccsrc/backend/optimizer/somas/somas_stream.cc
deleted file mode 100644
index 20cd8b1b3f..0000000000
--- a/mindspore/ccsrc/backend/optimizer/somas/somas_stream.cc
+++ /dev/null
@@ -1,53 +0,0 @@
-/**
- * Copyright 2020 Huawei Technologies Co., Ltd
-
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
-
- * http://www.apache.org/licenses/LICENSE-2.0
-
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
-*/
-
-#include "backend/optimizer/somas/somas_stream.h"
-
-namespace mindspore {
-namespace somas {
-void SomasStream::ComputeAncestorStreams() {
-  // (Naive) algorithm: for a given stream, compute its ancestors assuming only distance 1 ancestors are known (handles
-  // cycles between streams)
-  std::set<SomasStreamPtr> current_level, temp_level, already_visited;
-  auto thisPtr = std::make_shared<SomasStream>(id_);
-  already_visited.insert(thisPtr);
-  // Initialize current level to distance 2 ancestors
-  for (auto stream1 : ancestor_streams_) {
-    already_visited.insert(stream1);
-    for (auto stream2 : stream1->ancestor_streams_) {
-      if (std::find(already_visited.begin(), already_visited.end(), stream2) == already_visited.end())
-        current_level.insert(stream2);
-    }
-  }
-
-  while (!current_level.empty()) {
-    // Push current level into ancestors
-    for (auto stream1 : current_level) {
-      ancestor_streams_.insert(stream1);
-      already_visited.insert(stream1);
-      // Keep next level of this ancestor
-      for (auto stream2 : stream1->ancestor_streams_) {
-        if (std::find(already_visited.begin(), already_visited.end(), stream2) == already_visited.end())
-          temp_level.insert(stream2);
-      }
-    }
-    current_level.clear();
-    current_level = temp_level;
-    temp_level.clear();
-  }
-}
-}  // namespace somas
-}  // namespace mindspore
diff --git a/mindspore/ccsrc/backend/optimizer/somas/somas_stream.h b/mindspore/ccsrc/backend/optimizer/somas/somas_stream.h
index c924eb47de..2c6f9ccdfc 100644
--- a/mindspore/ccsrc/backend/optimizer/somas/somas_stream.h
+++ b/mindspore/ccsrc/backend/optimizer/somas/somas_stream.h
@@ -51,9 +51,6 @@ class SomasStream {
   // Accessors
   const int64_t &GetId() const { return id_; }
 
-  // Ancestor Computing
-  void ComputeAncestorStreams();  // Given "ancestors at distance one" information, compute "ancestors at any distance"
-
  private:
   const int64_t id_{0};
 };