From: Bruno Turcksin <bruno.turcksin@gmail.com>
Date: Wed, 2 Mar 2016 21:06:34 +0000 (-0500)
Subject: Filter range given an arbitrary number of IteratorFilters.
X-Git-Tag: v8.5.0-rc1~1250^2~2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8bef88f4124fab790a2a7d7758d73ca13a1b2ddf;p=dealii.git

Filter range given an arbitrary number of IteratorFilters.
---

diff --git a/include/deal.II/grid/filtered_iterator.h b/include/deal.II/grid/filtered_iterator.h
index 3ba88db584..82344cebca 100644
--- a/include/deal.II/grid/filtered_iterator.h
+++ b/include/deal.II/grid/filtered_iterator.h
@@ -19,6 +19,7 @@
 
 #include <deal.II/base/config.h>
 #include <deal.II/base/exceptions.h>
+#include <deal.II/base/iterator_range.h>
 #include <deal.II/grid/tria_iterator_base.h>
 
 #include <set>
@@ -771,6 +772,99 @@ make_filtered_iterator (const BaseIterator &i,
 
 
 
+#ifdef DEAL_II_WITH_CXX11
+/**
+ * Filter the  given range of iterators using a Predicate. This allows to replace:
+ * @code
+ *   DoFHandler<dim> dof_handler;
+ *   ...
+ *   for (auto cell : dof_handler.active_cell_iterators())
+ *     {
+ *       if (cell->is_locally_owned())
+ *         {
+ *           fe_values.reinit (cell);
+ *           ...do the local integration on 'cell'...;
+ *         }
+ *     }
+ * @endcode
+ * by:
+ * @code
+ *   DoFHandler<dim> dof_handler;
+ *   ...
+ *   for (auto cell : filter_iterators(dof_handler.active_cell_iterators(),
+ *                                    IteratorFilters::LocallyOwned())
+ *     {
+ *       fe_values.reinit (cell);
+ *       ...do the local integration on 'cell'...;
+ *     }
+ * @endcode
+ *
+ * @author Bruno Turcksin 
+ * @relates FilteredIterator 
+ * @ingroup CPP11
+ */
+template <typename BaseIterator, typename Predicate>
+IteratorRange<FilteredIterator<BaseIterator> >
+filter_iterators (IteratorRange<BaseIterator> i,
+                  const Predicate &p)
+{
+  FilteredIterator<BaseIterator> fi(p, *(i.begin()));
+  FilteredIterator<BaseIterator> fi_end(p, *(i.end()));
+
+  return IteratorRange<FilteredIterator<BaseIterator> > (fi, fi_end);
+}
+#endif
+
+
+
+#ifdef DEAL_II_WITH_CXX14
+/**
+ * Filter the given of iterators an arbitrary number of Predicates. This allows
+ * to replace:
+ * @code
+ *   DoFHandler<dim> dof_handler;
+ *   ...
+ *   for (auto cell : dof_handler.active_cell_iterators())
+ *     {
+ *       if (cell->is_locally_owned())
+ *         {
+ *           if (cell->at_boundary())
+ *             {
+ *               fe_values.reinit (cell);
+ *               ...do the local integration on 'cell'...;
+ *             }
+ *         }
+ *     }
+ * @endcode
+ * by:
+ * @code
+ *   DoFHandler<dim> dof_handler;
+ *   ...
+ *   for (auto cell : filter_iterators(dof_handler.active_cell_iterators(),
+ *                                    IteratorFilters::LocallyOwned(),
+ *                                    IteratorFilters::AtBoundary())
+ *     {
+ *       fe_values.reinit (cell);
+ *       ...do the local integration on 'cell'...;
+ *     }
+ * @endcode
+ *
+ * @note This function requires C++14
+ *
+ * @author Bruno Turcksin
+ * @relates FilteredIterator
+ */
+template <typename BaseIterator, typename Predicate, typename... Targs>
+auto
+filter_iterators (IteratorRange<BaseIterator> i,
+                  const Predicate &p, const Targs... args)
+{
+  auto fi = filter_iterators(i,p);
+  return filter_iterators(fi, args...);
+}
+#endif
+
+
 /* ------------------ Inline functions and templates ------------ */
 
 
diff --git a/tests/grid/filtered_iterator_04.cc b/tests/grid/filtered_iterator_04.cc
index 2cae8c50d0..0742facba1 100644
--- a/tests/grid/filtered_iterator_04.cc
+++ b/tests/grid/filtered_iterator_04.cc
@@ -14,7 +14,7 @@
 // ---------------------------------------------------------------------
 
 
-// check filtered iterators using two predicate
+// check filtered iterators using multiple predicate
 
 #include "../tests.h"
 #include <deal.II/base/logstream.h>
@@ -57,15 +57,11 @@ void test ()
     if ((cell->subdomain_id()==0) && (cell->at_boundary()))
       cell_set.insert(cell);
 
-  const IteratorFilters::AtBoundary predicate_1;
-  const IteratorFilters::SubdomainEqualTo predicate_2(0);
-  FilteredIterator<active_cell_iterator> fi_cell(predicate_1),
-                   end_fi_cell(predicate_1, tria.end());
-  fi_cell.set_to_next_positive(tria.begin_active());
-  FilteredIterator<FilteredIterator<active_cell_iterator> > filtered_cell(predicate_2, fi_cell),
-                   end_filtered_cell(predicate_2, end_fi_cell);
+
   unsigned int n_filtered_cells = 0;
-  for (; filtered_cell!=end_filtered_cell; ++filtered_cell)
+  for (auto filtered_cell : filter_iterators(tria.active_cell_iterators(),
+                                             IteratorFilters::AtBoundary(),
+                                             IteratorFilters::SubdomainEqualTo(0)))
     {
       AssertThrow(cell_set.count(filtered_cell)==1, ExcMessage("Wrong cell filtered."));
       ++n_filtered_cells;
diff --git a/tests/grid/filtered_iterator_04.output b/tests/grid/filtered_iterator_04.with_cxx11=true.output
similarity index 100%
rename from tests/grid/filtered_iterator_04.output
rename to tests/grid/filtered_iterator_04.with_cxx11=true.output