add in sync

src/tree/updater.cpp

@@ -2,6 +2,7 @@
 #define _CRT_SECURE_NO_DEPRECATE
 #include <cstring>
 #include "./updater.h"
+#include "./updater_sync-inl.hpp"
 #include "./updater_prune-inl.hpp"
 #include "./updater_refresh-inl.hpp"
 #include "./updater_colmaker-inl.hpp"
@@ -13,6 +14,7 @@ namespace tree {
 IUpdater* CreateUpdater(const char *name) {
   using namespace std;
   if (!strcmp(name, "prune")) return new TreePruner();
+  if (!strcmp(name, "sync")) return new TreeSyncher();
   if (!strcmp(name, "refresh")) return new TreeRefresher<GradStats>();
   if (!strcmp(name, "grow_colmaker")) return new ColMaker<GradStats>();
   if (!strcmp(name, "grow_qhistmaker")) return new QuantileHistMaker<GradStats>();

src/tree/updater_colmaker-inl.hpp

@@ -14,7 +14,7 @@
 
 namespace xgboost {
 namespace tree {
-/*! \brief pruner that prunes a tree after growing finishs */
+/*! \brief colunwise update to construct a tree */
 template<typename TStats>
 class ColMaker: public IUpdater {
  public:

src/tree/updater_prune-inl.hpp

@@ -8,7 +8,7 @@
 #include <vector>
 #include "./param.h"
 #include "./updater.h"
-#include "../sync/sync.h"
+#include "./updater_sync-inl.hpp"
 
 namespace xgboost {
 namespace tree {
@@ -20,6 +20,7 @@ class TreePruner: public IUpdater {
   virtual void SetParam(const char *name, const char *val) {
     using namespace std;
     param.SetParam(name, val);
+    syncher.SetParam(name, val);
     if (!strcmp(name, "silent")) silent = atoi(val);
   }
   // update the tree, do pruning
@@ -34,27 +35,9 @@ class TreePruner: public IUpdater {
       this->DoPrune(*trees[i]);
     }
     param.learning_rate = lr;
-    this->SyncTrees(trees);
+    syncher.Update(gpair, p_fmat, info, trees);
   }
  private:
-  // synchronize the trees in different nodes, take tree from rank 0
-  inline void SyncTrees(const std::vector<RegTree *> &trees) {
-    if (sync::GetWorldSize() == 1) return;
-    std::string s_model;
-    utils::MemoryBufferStream fs(&s_model);
-    int rank = sync::GetRank();
-    if (rank == 0) {
-      for (size_t i = 0; i < trees.size(); ++i) {
-        trees[i]->SaveModel(fs);
-      }
-      sync::Bcast(&s_model, 0);
-    } else {
-      sync::Bcast(&s_model, 0);
-      for (size_t i = 0; i < trees.size(); ++i) {      
-        trees[i]->LoadModel(fs);
-      }
-    }
-  }
   // try to prune off current leaf
   inline int TryPruneLeaf(RegTree &tree, int nid, int depth, int npruned) {
     if (tree[nid].is_root()) return npruned;
@@ -89,6 +72,8 @@ class TreePruner: public IUpdater {
   }
 
  private:
+  // synchronizer
+  TreeSyncher syncher;
   // shutup
   int silent;
   // training parameter

src/tree/updater_sync-inl.hpp

@@ -0,0 +1,54 @@
+#ifndef XGBOOST_TREE_UPDATER_SYNC_INL_HPP_
+#define XGBOOST_TREE_UPDATER_SYNC_INL_HPP_
+/*!
+ * \file updater_sync-inl.hpp
+ * \brief synchronize the tree in all distributed nodes
+ * \author Tianqi Chen
+ */
+#include <vector>
+#include <limits>
+#include "./updater.h"
+#include "../sync/sync.h"
+
+namespace xgboost {
+namespace tree {
+/*! 
+ * \brief syncher that synchronize the tree in all distributed nodes
+ * can implement various strategies, so far it is always set to node 0's tree
+ */
+class TreeSyncher: public IUpdater {
+ public:
+  virtual ~TreeSyncher(void) {}
+  virtual void SetParam(const char *name, const char *val) {
+  }
+  // update the tree, do pruning
+  virtual void Update(const std::vector<bst_gpair> &gpair,
+                      IFMatrix *p_fmat,
+                      const BoosterInfo &info,
+                      const std::vector<RegTree*> &trees) {
+    this->SyncTrees(trees);
+  }
+  
+ private:
+  // synchronize the trees in different nodes, take tree from rank 0
+  inline void SyncTrees(const std::vector<RegTree *> &trees) {
+    if (sync::GetWorldSize() == 1) return;
+    std::string s_model;
+    utils::MemoryBufferStream fs(&s_model);
+    int rank = sync::GetRank();
+    if (rank == 0) {
+      for (size_t i = 0; i < trees.size(); ++i) {
+        trees[i]->SaveModel(fs);
+      }
+      sync::Bcast(&s_model, 0);
+    } else {
+      sync::Bcast(&s_model, 0);
+      for (size_t i = 0; i < trees.size(); ++i) {      
+        trees[i]->LoadModel(fs);
+      }
+    }
+  }    
+};
+}  // namespace tree
+}  // namespace xgboost
+#endif  // XGBOOST_TREE_UPDATER_SYNC_INL_HPP_