implement louvain algorithm

analytical_engine/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.1)
 
 if ("${GRAPHSCOPE_VERSION}" STREQUAL "")
     set(GRAPHSCOPE_ANALYTICAL_MAJOR_VERSION 0)
@@ -45,7 +45,9 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 include_directories(${PROJECT_SOURCE_DIR})
 
 # Set flags
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14 -Wall")
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99")
 if (APPLE)
     set(CMAKE_MACOSX_RPATH ON)

analytical_engine/apps/pregel/louvain/auxiliary.h

@@ -0,0 +1,185 @@
+/** Copyright 2020 Alibaba Group Holding Limited.
+ *
+ * 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.
+ */
+
+#ifndef ANALYTICAL_ENGINE_APPS_PREGEL_LOUVAIN_AUXILIARY_H_
+#define ANALYTICAL_ENGINE_APPS_PREGEL_LOUVAIN_AUXILIARY_H_
+
+#include <map>
+#include <vector>
+
+#include "grape/grape.h"
+
+namespace gs {
+
+// aggregators define
+constexpr char change_aggregator[] = "change_aggregator";
+constexpr char edge_weight_aggregator[] = "total_edge_weight_aggregator";
+constexpr char actual_quality_aggregator[] = "actual_quality_aggregator";
+
+// major phase of louvain
+constexpr int phase_one_start_step = 0;
+constexpr int phase_two_start_step = -2;
+constexpr int compress_community_step = -1;
+constexpr int sync_result_step = -10;
+constexpr int terminate_step = -9;
+
+// minor step of phase 1
+constexpr int phase_one_minor_step_0 = 0;
+constexpr int phase_one_minor_step_1 = 1;
+constexpr int phase_one_minor_step_2 = 2;
+
+/**
+ * The state of a vertex.
+ */
+template <typename VID_T>
+struct LouvainNodeState {
+  using vid_t = VID_T;
+  using edata_t = double;
+
+  vid_t community = 0;
+  edata_t community_sigma_total;
+
+  // the internal edge weight of a node
+  edata_t internal_weight;
+
+  // degree of the node
+  edata_t node_weight;
+
+  // 1 if the node has changed communities this cycle, otherwise 0
+  int64_t changed;
+
+  bool reset_total_edge_weight;
+  bool is_from_louvain_vertex_reader = false;
+  bool use_fake_edges = false;
+  bool is_alived_community = true;
+
+  std::map<vid_t, edata_t> fake_edges;
+  std::vector<vid_t> nodes_in_community;
+  edata_t total_edge_weight;
+
+  LouvainNodeState()
+      : community(0),
+        community_sigma_total(0.0),
+        internal_weight(0.0),
+        node_weight(0.0),
+        changed(0),
+        reset_total_edge_weight(false),
+        is_from_louvain_vertex_reader(false),
+        use_fake_edges(false),
+        is_alived_community(true) {}
+
+  ~LouvainNodeState() = default;
+};
+
+/**
+ * Message type of louvain.
+ */
+template <typename VID_T>
+struct LouvainMessage {
+  using vid_t = VID_T;
+  using edata_t = double;
+
+  vid_t community_id;
+  edata_t community_sigma_total;
+  edata_t edge_weight;
+  vid_t source_id;
+  vid_t dst_id;
+
+  // For reconstruct graph info.
+  // Each vertex send self's meta info to its community and silence itself,
+  // the community compress its member's data and make self a new vertex for
+  // next phase.
+  edata_t internal_weight = 0;
+  std::map<vid_t, edata_t> edges;
+  std::vector<vid_t> nodes_in_self_community;
+
+  LouvainMessage()
+      : community_id(0),
+        community_sigma_total(0.0),
+        edge_weight(0.0),
+        source_id(0),
+        dst_id(0) {}
+
+  LouvainMessage(const vid_t& community_id, edata_t community_sigma_total,
+                 edata_t edge_weight, const vid_t& source_id,
+                 const vid_t& dst_id)
+      : community_id(community_id),
+        community_sigma_total(community_sigma_total),
+        edge_weight(edge_weight),
+        source_id(source_id),
+        dst_id(dst_id) {}
+
+  ~LouvainMessage() = default;
+
+  // for message manager to serialize and diserialize LouvainMessage
+  friend grape::InArchive& operator<<(grape::InArchive& in_archive,
+                                      const LouvainMessage& u) {
+    in_archive << u.community_id;
+    in_archive << u.community_sigma_total;
+    in_archive << u.edge_weight;
+    in_archive << u.source_id;
+    in_archive << u.dst_id;
+    in_archive << u.internal_weight;
+    in_archive << u.edges;
+    in_archive << u.nodes_in_self_community;
+    return in_archive;
+  }
+  friend grape::OutArchive& operator>>(grape::OutArchive& out_archive,
+                                       LouvainMessage& val) {
+    out_archive >> val.community_id;
+    out_archive >> val.community_sigma_total;
+    out_archive >> val.edge_weight;
+    out_archive >> val.source_id;
+    out_archive >> val.dst_id;
+    out_archive >> val.internal_weight;
+    out_archive >> val.edges;
+    out_archive >> val.nodes_in_self_community;
+    return out_archive;
+  }
+};
+
+/**
+ * Determine if progress is still being made or if the computaion should halt.
+ *
+ * @param history change history of the pass.
+ * @param min_progress The minimum delta X required to be considered progress.
+ * where X is the number of nodes that have changed their community on a
+ * particular pass.
+ * @param progress_tries Number of times the minimum.progress setting is not met
+ * before exiting form the current level and compressing the graph
+ * @return true
+ * @return false
+ */
+bool decide_to_halt(const std::vector<int64_t>& history, int min_progress,
+                    int progress_tries) {
+  // halt if the most recent change was 0
+  if (0 == history.back()) {
+    return true;
+  }
+  // halt if the change count has increased progress_tries times
+  int64_t previous = history.front();
+  int count = 0;
+  for (const auto& cur : history) {
+    if (previous - cur <= min_progress) {
+      count++;
+    }
+    previous = cur;
+  }
+  return (count > progress_tries);
+}
+
+}  // namespace gs
+
+#endif  // ANALYTICAL_ENGINE_APPS_PREGEL_LOUVAIN_AUXILIARY_H_