[TREE] Enable updater registry

src/common/io.h

@@ -0,0 +1,20 @@
+/*!
+ * Copyright 2014 by Contributors
+ * \file io.h
+ * \brief general stream interface for serialization, I/O
+ * \author Tianqi Chen
+ */
+
+#ifndef XGBOOST_COMMON_IO_H_
+#define XGBOOST_COMMON_IO_H_
+
+#include <dmlc/io.h>
+#include "./sync.h"
+
+namespace xgboost {
+namespace common {
+typedef rabit::utils::MemoryFixSizeBuffer MemoryFixSizeBuffer;
+typedef rabit::utils::MemoryBufferStream MemoryBufferStream;
+}  // namespace common
+}  // namespace xgboost
+#endif  // XGBOOST_COMMON_IO_H_

src/common/sync.h

@@ -0,0 +1,13 @@
+/*!
+ * Copyright 2014 by Contributors
+ * \file sync.h
+ * \brief the synchronization module of rabit
+ *        redirects to rabit header
+ * \author Tianqi Chen
+ */
+#ifndef XGBOOST_COMMON_SYNC_H_
+#define XGBOOST_COMMON_SYNC_H_
+
+#include <rabit.h>
+
+#endif  // XGBOOST_SYNC_H_

src/global.cc

@@ -5,11 +5,12 @@
  */
 #include <xgboost/objective.h>
 #include <xgboost/metric.h>
-#include <xgboost/tree_model.h>
+#include <xgboost/tree_updater.h>
 
 namespace dmlc {
 DMLC_REGISTRY_ENABLE(::xgboost::ObjFunctionReg);
 DMLC_REGISTRY_ENABLE(::xgboost::MetricReg);
+DMLC_REGISTRY_ENABLE(::xgboost::TreeUpdaterReg);
 }  // namespace dmlc
 
 namespace xgboost {
@@ -42,8 +43,14 @@ Metric* Metric::Create(const char* name) {
   }
 }
 
-void test() {
-  RegTree tree;
+// implement factory functions
+TreeUpdater* TreeUpdater::Create(const char* name) {
+  auto *e = ::dmlc::Registry< ::xgboost::TreeUpdaterReg>::Get()->Find(name);
+  if (e == nullptr) {
+    LOG(FATAL) << "Unknown tree updater " << name;
+  }
+  return (e->body)();
 }
+
 }  // namespace xgboost
 

src/metric/elementwise_metric.cc

@@ -5,9 +5,9 @@
  * \author Kailong Chen, Tianqi Chen
  */
 #include <xgboost/metric.h>
-#include <xgboost/sync.h>
 #include <cmath>
 #include "../common/math.h"
+#include "../common/sync.h"
 
 namespace xgboost {
 namespace metric {

src/metric/multiclass_metric.cc

@@ -5,8 +5,8 @@
  * \author Kailong Chen, Tianqi Chen
  */
 #include <xgboost/metric.h>
-#include <xgboost/sync.h>
 #include <cmath>
+#include "../common/sync.h"
 #include "../common/math.h"
 
 namespace xgboost {

src/metric/rank_metric.cc

@@ -5,8 +5,8 @@
  * \author Kailong Chen, Tianqi Chen
  */
 #include <xgboost/metric.h>
-#include <xgboost/sync.h>
 #include <cmath>
+#include "../common/sync.h"
 #include "../common/math.h"
 
 namespace xgboost {

src/tree/tree_model.cc

@@ -6,8 +6,9 @@
 #include <xgboost/tree_model.h>
 #include <sstream>
 
-
 namespace xgboost {
+// register tree parameter
+DMLC_REGISTER_PARAMETER(TreeParam);
 
 // internal function to dump regression tree to text
 void DumpRegTree2Text(std::stringstream& fo,  // NOLINT(*)

src/tree/updater_sync.cc

@@ -0,0 +1,50 @@
+/*!
+ * Copyright 2014 by Contributors
+ * \file updater_sync.cc
+ * \brief synchronize the tree in all distributed nodes
+ */
+#include <xgboost/tree_updater.h>
+#include <vector>
+#include <string>
+#include <limits>
+#include "../common/sync.h"
+#include "../common/io.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 TreeUpdater {
+ public:
+  void Init(const std::vector<std::pair<std::string, std::string> >& args) override {}
+
+  void Update(const std::vector<bst_gpair> &gpair,
+              DMatrix* dmat,
+              const std::vector<RegTree*> &trees) override {
+    if (rabit::GetWorldSize() == 1) return;
+    std::string s_model;
+    common::MemoryBufferStream fs(&s_model);
+    int rank = rabit::GetRank();
+    if (rank == 0) {
+      for (size_t i = 0; i < trees.size(); ++i) {
+        trees[i]->SaveModel(&fs);
+      }
+    }
+    fs.Seek(0);
+    rabit::Broadcast(&s_model, 0);
+    for (size_t i = 0; i < trees.size(); ++i) {
+      trees[i]->LoadModel(&fs);
+    }
+  }
+};
+
+XGBOOST_REGISTER_TREE_UPDATER(TreeSyncher, "sync")
+.describe("Syncher that synchronize the tree in all distributed nodes.")
+.set_body([]() {
+    return new TreeSyncher();
+  });
+}  // namespace tree
+}  // namespace xgboost
+