From 16585b0c88d0452bd7d486ea5292695f18d1747c Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@math.tamu.edu>
Date: Thu, 19 Jun 2014 23:34:38 +0000
Subject: [PATCH] Patch by Denis Davydov: Introduce n_global_active_cells()
 also in dealii::Triangulation.

git-svn-id: https://svn.dealii.org/trunk@33062 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/doc/news/changes.h                 |  5 +++++
 deal.II/include/deal.II/distributed/tria.h |  2 +-
 deal.II/include/deal.II/grid/tria.h        | 10 ++++++++++
 deal.II/source/grid/tria.cc                |  7 +++++++
 4 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/deal.II/doc/news/changes.h b/deal.II/doc/news/changes.h
index 7b1c9edc11..957f6ddb4d 100644
--- a/deal.II/doc/news/changes.h
+++ b/deal.II/doc/news/changes.h
@@ -162,6 +162,11 @@ inconvenience this causes.
   (Denis Davydov, 2014/06/15)
   </li>
 
+  <li> New: There is now function Triangulation::n_global_active_cells().
+  <br>
+  (Denis Davydov, 2014/06/19)
+  </li>
+
   <li> New: There is now a class FEEvaluationQ_DG0 that does
   optimized matrix-free evaluation for FE_Q_DG0 elements.
   <br>
diff --git a/deal.II/include/deal.II/distributed/tria.h b/deal.II/include/deal.II/distributed/tria.h
index 7e0f4e06db..ea3e88bc09 100644
--- a/deal.II/include/deal.II/distributed/tria.h
+++ b/deal.II/include/deal.II/distributed/tria.h
@@ -492,7 +492,7 @@ namespace parallel
        * cells owned by each processor. This equals the overall number
        * of active cells in the distributed triangulation.
        */
-      types::global_dof_index n_global_active_cells () const;
+      virtual types::global_dof_index n_global_active_cells () const;
 
       /**
        * Returns the global maximum level. This may be bigger than
diff --git a/deal.II/include/deal.II/grid/tria.h b/deal.II/include/deal.II/grid/tria.h
index f60fd6e545..a8f7154342 100644
--- a/deal.II/include/deal.II/grid/tria.h
+++ b/deal.II/include/deal.II/grid/tria.h
@@ -2850,6 +2850,16 @@ public:
    */
   unsigned int n_active_cells () const;
 
+  /**
+   * Return the total number of active cells. For the current class, this is
+   * the same as n_active_cells(). However, the function may be overloaded in
+   * derived classes (e.g., in parallel::distributed::Triangulation) where it
+   * may return a value greater than the number of active cells reported by
+   * the triangulation object on the current processor.
+   */
+  virtual types::global_dof_index n_global_active_cells () const;
+
+
   /**
    * Return total number of active cells on
    * level @p level.  Maps to
diff --git a/deal.II/source/grid/tria.cc b/deal.II/source/grid/tria.cc
index 2193762bea..6d1a054920 100644
--- a/deal.II/source/grid/tria.cc
+++ b/deal.II/source/grid/tria.cc
@@ -11462,6 +11462,13 @@ unsigned int Triangulation<dim, spacedim>::n_active_cells () const
   return internal::Triangulation::n_active_cells (number_cache);
 }
 
+template <int dim, int spacedim>
+types::global_dof_index Triangulation<dim, spacedim>::n_global_active_cells () const
+{
+  return n_active_cells();
+}
+
+
 
 template <int dim, int spacedim>
 unsigned int Triangulation<dim, spacedim>::n_faces () const
-- 
2.39.5