[PYTHON-DIST] Distributed xgboost python training API.

src/tree/updater_basemaker-inl.h

@@ -56,6 +56,9 @@ class BaseMaker: public TreeUpdater {
           }
         }
       }
+    }
+    /*! \brief synchronize the information */
+    inline void SyncInfo() {
       rabit::Allreduce<rabit::op::Max>(dmlc::BeginPtr(fminmax), fminmax.size());
     }
     // get feature type, 0:empty 1:binary 2:real

src/tree/updater_histmaker.cc

@@ -313,6 +313,7 @@ class CQHistMaker: public HistMaker<TStats> {
       feat_helper.InitByCol(p_fmat, tree);
       cache_dmatrix_ = p_fmat;
     }
+    feat_helper.SyncInfo();
     feat_helper.SampleCol(this->param.colsample_bytree, p_fset);
   }
   // code to create histogram