From 42ccce4acc9dd5c6b59c5eac3542004641cf5837 Mon Sep 17 00:00:00 2001
From: Fernando Herrera <cafeherval@gmail.com>
Date: Sat, 17 Aug 2024 20:25:19 -0600
Subject: [PATCH] Add empty() function to deal.II/hp/collection.h and use it
 instead of size() == 0

This only changes files in the source directory
---
 include/deal.II/hp/collection.h    | 15 +++++++++++++++
 source/distributed/cell_weights.cc |  2 +-
 source/hp/fe_collection.cc         |  2 +-
 source/hp/refinement.cc            | 22 +++++++++++-----------
 4 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/include/deal.II/hp/collection.h b/include/deal.II/hp/collection.h
index 0f65f10a98..92431efcca 100644
--- a/include/deal.II/hp/collection.h
+++ b/include/deal.II/hp/collection.h
@@ -252,6 +252,12 @@ namespace hp
     unsigned int
     size() const;
 
+    /**
+     * This is equivalent to <code>size() == 0</code>
+     */
+    bool
+    empty() const;
+
     /**
      * Determine an estimate for the memory consumption (in bytes) of this
      * object.
@@ -312,6 +318,15 @@ namespace hp
 
 
 
+  template <typename T>
+  inline bool
+  Collection<T>::empty() const
+  {
+    return this->size() == 0;
+  }
+
+
+
   template <typename T>
   inline const T &
   Collection<T>::operator[](const unsigned int index) const
diff --git a/source/distributed/cell_weights.cc b/source/distributed/cell_weights.cc
index 9707262e65..16a88760f4 100644
--- a/source/distributed/cell_weights.cc
+++ b/source/distributed/cell_weights.cc
@@ -175,7 +175,7 @@ namespace parallel
     (void)triangulation;
 
     // Skip if the DoFHandler has not been initialized yet.
-    if (dof_handler.get_fe_collection().size() == 0)
+    if (dof_handler.get_fe_collection().empty())
       return 0;
 
     // Convert cell type from Triangulation to DoFHandler to be able
diff --git a/source/hp/fe_collection.cc b/source/hp/fe_collection.cc
index ca1e1342d8..2669f7e7e6 100644
--- a/source/hp/fe_collection.cc
+++ b/source/hp/fe_collection.cc
@@ -67,7 +67,7 @@ namespace hp
     // check that the new element has the right number of components. only check
     // with the first element, since all the other elements have already passed
     // the test against the first element
-    Assert(this->size() == 0 ||
+    Assert(this->empty() ||
              new_fe.n_components() == this->operator[](0).n_components(),
            ExcMessage("All elements inside a collection need to have the "
                       "same number of vector components!"));
diff --git a/source/hp/refinement.cc b/source/hp/refinement.cc
index 8e57fd28da..44199edb3f 100644
--- a/source/hp/refinement.cc
+++ b/source/hp/refinement.cc
@@ -48,7 +48,7 @@ namespace hp
     void
     full_p_adaptivity(const DoFHandler<dim, spacedim> &dof_handler)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -68,7 +68,7 @@ namespace hp
     p_adaptivity_from_flags(const DoFHandler<dim, spacedim> &dof_handler,
                             const std::vector<bool>         &p_flags)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -117,7 +117,7 @@ namespace hp
       const ComparisonFunction<std_cxx20::type_identity_t<Number>>
         &compare_coarsen)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -156,7 +156,7 @@ namespace hp
       const ComparisonFunction<std_cxx20::type_identity_t<Number>>
         &compare_coarsen)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -253,7 +253,7 @@ namespace hp
       const ComparisonFunction<std_cxx20::type_identity_t<Number>>
         &compare_coarsen)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -447,7 +447,7 @@ namespace hp
     p_adaptivity_from_regularity(const DoFHandler<dim, spacedim> &dof_handler,
                                  const Vector<Number> &sobolev_indices)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -509,7 +509,7 @@ namespace hp
       const ComparisonFunction<std_cxx20::type_identity_t<Number>>
         &compare_coarsen)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -550,7 +550,7 @@ namespace hp
                   const double                     gamma_h,
                   const double                     gamma_n)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -677,7 +677,7 @@ namespace hp
     void
     force_p_over_h(const DoFHandler<dim, spacedim> &dof_handler)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -698,7 +698,7 @@ namespace hp
     void
     choose_p_over_h(const DoFHandler<dim, spacedim> &dof_handler)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return;
 
@@ -811,7 +811,7 @@ namespace hp
                              const unsigned int               max_difference,
                              const unsigned int               contains_fe_index)
     {
-      if (dof_handler.get_fe_collection().size() == 0)
+      if (dof_handler.get_fe_collection().empty())
         // nothing to do
         return false;
 
-- 
2.39.5