From e5663536014962a42a94d3fdb08e2d680aa41443 Mon Sep 17 00:00:00 2001
From: Jiaqi Zhang <jiaqi2@clemson.edu>
Date: Wed, 21 Jul 2021 15:09:48 +0000
Subject: [PATCH] add table.clear()

---
 include/deal.II/base/table.h | 16 ++++++++++++++++
 tests/base/table_05.cc       |  3 +++
 tests/base/table_07.cc       |  3 +++
 3 files changed, 22 insertions(+)

diff --git a/include/deal.II/base/table.h b/include/deal.II/base/table.h
index 0590896869..7eb422369f 100644
--- a/include/deal.II/base/table.h
+++ b/include/deal.II/base/table.h
@@ -543,6 +543,12 @@ public:
   reinit(const TableIndices<N> &new_size,
          const bool             omit_default_initialization = false);
 
+  /**
+   * Set all dimensions to zero.
+   */
+  void
+  clear();
+
   /**
    * Size of the table in direction <tt>i</tt>.
    */
@@ -2421,6 +2427,16 @@ TableBase<N, T>::reinit(const TableIndices<N> &new_sizes,
 
 
 
+template <int N, typename T>
+inline void
+TableBase<N, T>::clear()
+{
+  values.resize(0);
+  table_size = TableIndices<N>();
+}
+
+
+
 template <int N, typename T>
 inline const TableIndices<N> &
 TableBase<N, T>::size() const
diff --git a/tests/base/table_05.cc b/tests/base/table_05.cc
index 9411790dc8..bdb9cc305a 100644
--- a/tests/base/table_05.cc
+++ b/tests/base/table_05.cc
@@ -31,6 +31,9 @@ test()
   dealii::Table<dim, int> unrolled;
   unrolled.reinit(new_size);
 
+  unrolled.clear();
+  Assert(unrolled.empty() == true, ExcInternalError());
+
   deallog << "OK" << std::endl;
 }
 
diff --git a/tests/base/table_07.cc b/tests/base/table_07.cc
index a9734402c9..b7856ad535 100644
--- a/tests/base/table_07.cc
+++ b/tests/base/table_07.cc
@@ -54,5 +54,8 @@ main()
   dealii::Table<2, T> table2;
   table2 = std::move(table); // should not create new objects
 
+  table.clear();
+  Assert(table.empty() == true, ExcInternalError());
+
   deallog << "OK" << std::endl;
 }
-- 
2.39.5