From 1f1eda5c97c2cdb76f4c5c241ef192d9e67ce0ed Mon Sep 17 00:00:00 2001
From: Hans Dembinski <hans.dembinski@gmail.com>
Date: Mon, 27 Sep 2021 10:26:27 +0200
Subject: [PATCH] added comment about proven usefulness of this optimization

---
 include/boost/histogram/detail/fill_n.hpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/boost/histogram/detail/fill_n.hpp b/include/boost/histogram/detail/fill_n.hpp
index 128bc4c1..520b301e 100644
--- a/include/boost/histogram/detail/fill_n.hpp
+++ b/include/boost/histogram/detail/fill_n.hpp
@@ -242,6 +242,7 @@ void fill_n_1(const std::size_t offset, S& storage, A& axes, const std::size_t v
   for_each_axis(axes,
                 [&](const auto& ax) { all_inclusive &= axis::traits::inclusive(ax); });
   if (axes_rank(axes) == 1) {
+    // Optimization: benchmark shows that this makes filling dynamic 1D histogram faster
     axis::visit(
         [&](auto& ax) {
           std::tuple<decltype(ax)> axes{ax};