added empty(), and changed inheritance

git-svn-id: https://svn.dealii.org/trunk@7667 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/lac/include/lac/sparse_decomposition.h b/deal.II/lac/include/lac/sparse_decomposition.h
index 8877120d9e6f811147b278ba2fdf2cb170c26a16..5ba88fd694b6f9542b93d188bf365ed56b8b3f8a 100644 (file)
--- a/deal.II/lac/include/lac/sparse_decomposition.h
+++ b/deal.II/lac/include/lac/sparse_decomposition.h
@@ -119,7 +119,8 @@
  * Hartmann, 2003
  */
 template <typename number>
-class SparseLUDecomposition : protected SparseMatrix<number>
+class SparseLUDecomposition : protected SparseMatrix<number>, 
+                              public virtual Subscriptor
 {
   public:
 
@@ -283,6 +284,7 @@ class SparseLUDecomposition : protected SparseMatrix<number>
                                      * compability. It will be removed
                                      * in later versions.
                                      */
+
     void reinit ();
 
                                     /**
@@ -311,6 +313,13 @@ class SparseLUDecomposition : protected SparseMatrix<number>
                                       */ 
     virtual bool is_decomposed () const;       
 
+                                    /**
+                                     * Return whether the object is
+                                     * empty. It calls the inherited
+                                     * SparseMatrix::empty() function.
+                                     */
+    bool empty () const;
+
                                     /**
                                      * Determine an estimate for the
                                      * memory consumption (in bytes)
@@ -451,6 +460,15 @@ SparseLUDecomposition<number>::is_decomposed () const
 
 
 
+template <typename number>
+inline bool 
+SparseLUDecomposition<number>::empty () const 
+{
+  return SparseMatrix<number>::empty(); 
+}
+
+
+
 //----------------------------------------------------------------------//