From af1ae5114f3afe2a55d37fe81bdcffbc0b92f26c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mael=20Rouxel-Labb=C3=A9?=
 <mael.rouxel.labbe@geometryfactory.com>
Date: Thu, 2 Jan 2020 13:33:56 +0100
Subject: [PATCH] Update cutoffs under which sequential version is used
 regardless of tag

(after some experiments using random points in 2D/3D)
---
 Spatial_sorting/include/CGAL/Hilbert_sort_median_2.h | 2 +-
 Spatial_sorting/include/CGAL/Hilbert_sort_median_3.h | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/Spatial_sorting/include/CGAL/Hilbert_sort_median_2.h b/Spatial_sorting/include/CGAL/Hilbert_sort_median_2.h
index 3c0d5cdbc10..4b1ea293ad0 100644
--- a/Spatial_sorting/include/CGAL/Hilbert_sort_median_2.h
+++ b/Spatial_sorting/include/CGAL/Hilbert_sort_median_2.h
@@ -164,7 +164,7 @@ public:
 
     RandomAccessIterator m0 = begin, m4 = end;
 
-    if((end - begin) > 1024){
+    if((end - begin) > 8192){ // 2^13, empirically a good cutoff
       RandomAccessIterator m1, m2, m3;
       m2 = internal::hilbert_split (m0, m4, Cmp< x,  upx> (_k));
 
diff --git a/Spatial_sorting/include/CGAL/Hilbert_sort_median_3.h b/Spatial_sorting/include/CGAL/Hilbert_sort_median_3.h
index 5e8525bb7c1..0536ef8be94 100644
--- a/Spatial_sorting/include/CGAL/Hilbert_sort_median_3.h
+++ b/Spatial_sorting/include/CGAL/Hilbert_sort_median_3.h
@@ -179,14 +179,13 @@ public:
     if ((end - begin) <= _limit) return;
 
     RandomAccessIterator m0 = begin, m8 = end;
-    if((end - begin) > 1024){
+    if((end - begin) > 2048){ // 2^11, empirically a good cutoff
       RandomAccessIterator m1, m2, m3, m4, m5, m6, m7;
       m4 = internal::hilbert_split(m0, m8, Cmp<x, upx>(_k));
 
       tbb::parallel_invoke(Hilbert_split<RandomAccessIterator,Cmp<y,  upy> >(m2, m0, m4, Cmp<y,  upy>(_k)),
                            Hilbert_split<RandomAccessIterator,Cmp<y, !upy> >(m6, m4, m8, Cmp<y, !upy>(_k)));
 
-
       tbb::parallel_invoke(Hilbert_split<RandomAccessIterator,Cmp<z,  upz> >(m1, m0, m2, Cmp<z,  upz>(_k)),
                            Hilbert_split<RandomAccessIterator,Cmp<z, !upz> >(m3, m2, m4, Cmp<z, !upz>(_k)),
                            Hilbert_split<RandomAccessIterator,Cmp<z,  upz> >(m5, m4, m6, Cmp<z,  upz>(_k)),