From 32aef0d2196f4b3e91240cb15ce7f2b56ee5a57a Mon Sep 17 00:00:00 2001
From: Kirill Shvets <kirshvets@mail.ru>
Date: Sun, 26 Jun 2022 22:12:32 +0300
Subject: [PATCH] fix alreduce

---
 src/tree/hist/histogram.h | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/src/tree/hist/histogram.h b/src/tree/hist/histogram.h
index 8c461117cae7..459de8c40ca8 100644
--- a/src/tree/hist/histogram.h
+++ b/src/tree/hist/histogram.h
@@ -195,13 +195,8 @@ class HistogramBuilder {
           }
         });
 
-// <<<<<<< HEAD
-//     reducer_.Allreduce(this->hist_[starting_index].data(),
-//                        hist_.GetNumBins() * sync_count);
-// =======
     rabit::Allreduce<rabit::op::Sum>(reinterpret_cast<double*>(this->hist_[starting_index].data()),
-                                     hist_.GetNumBins() * sync_count);
-// >>>>>>> 0725fd60819f9758fbed6ee54f34f3696a2fb2f8
+                                     hist_.GetNumBins() * sync_count * 2);
 
     ParallelSubtractionHist(space, nodes_for_explicit_hist_build,
                             nodes_for_subtraction_trick, p_tree);