From ee17381e672430319ef47a545b77266747ad28b0 Mon Sep 17 00:00:00 2001
From: Peter Munch <peterrmuench@gmail.com>
Date: Mon, 22 Nov 2021 15:50:59 +0100
Subject: [PATCH] Add iterator traits to hp::CollectionIterator

---
 include/deal.II/hp/collection.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/deal.II/hp/collection.h b/include/deal.II/hp/collection.h
index ebce43e177..67b92615d6 100644
--- a/include/deal.II/hp/collection.h
+++ b/include/deal.II/hp/collection.h
@@ -293,4 +293,18 @@ namespace hp
 
 DEAL_II_NAMESPACE_CLOSE
 
+namespace std
+{
+  /**
+   * Iterator traits for hp::CollectionIterator.
+   */
+  template <class T>
+  struct iterator_traits<dealii::hp::CollectionIterator<T>>
+  {
+    using iterator_category = random_access_iterator_tag;
+    using value_type        = T;
+    using difference_type   = std::ptrdiff_t;
+  };
+} // namespace std
+
 #endif
-- 
2.39.5