* added method mmv

* added default constructor and made necessary changes for is to work, i.e.
    * made members pointers instead of references
    * allocate memory internally for lowRankFactor_ if default constructed
    * add destructor and delete lowRankFactor_in destructor if internally allocated
    * adapt uses of member
* added non const getter method for lowRankFactor_

[[Imported from SVN: r5477]]

dune/solvers/operators/lowrankoperator.hh

@@ -21,26 +21,40 @@ class LowRankOperator
         //! export size type
         typedef typename LRFactorType::size_type size_type;
 
+        //! default constructor
+        LowRankOperator():
+            factor_allocated_internally_(true)
+        {
+            lowRankFactor_ = new LowRankFactorType;
+        }
+
         //! constructor taking the defining factor as argument
         LowRankOperator(LowRankFactorType& lrFactor):
-            lowRankFactor_(lrFactor)
+            lowRankFactor_(&lrFactor),
+            factor_allocated_internally_(false)
         {}
 
+        ~LowRankOperator()
+        {
+            if (factor_allocated_internally_)
+                delete lowRankFactor_;
+        }
+
         //! b += Ax
         template <class LVectorType, class RVectorType>
         void umv(const LVectorType& x, RVectorType& b) const
         {
-            LVectorType temp(lowRankFactor_.N());
-            lowRankFactor_.mv(x,temp);
+            LVectorType temp(lowRankFactor_->N());
+            lowRankFactor_->mv(x,temp);
 
-            typename LowRankFactorType::RowIterator row_end = lowRankFactor_.end();
-            typename LowRankFactorType::RowIterator row_it = lowRankFactor_.begin();
+            typename LowRankFactorType::ConstRowIterator row_end = lowRankFactor_->end();
+            typename LowRankFactorType::ConstRowIterator row_it = lowRankFactor_->begin();
             for (; row_it!=row_end; ++row_it)
             {
-                typename LowRankFactorType::ColIterator col_end = row_it->end();
-                typename LowRankFactorType::ColIterator col_it = row_it->begin();
+                typename LowRankFactorType::ConstColIterator col_end = row_it->end();
+                typename LowRankFactorType::ConstColIterator col_it = row_it->begin();
                 for (; col_it!=col_end; ++col_it)
-                    lowRankFactor_[row_it.index()][col_it.index()].umv(temp[row_it.index()],b[col_it.index()]);
+                    (*lowRankFactor_)[row_it.index()][col_it.index()].umv(temp[row_it.index()],b[col_it.index()]);
             }
         }
 
@@ -48,17 +62,35 @@ class LowRankOperator
         template <class LVectorType, class RVectorType>
         void usmv(const field_type& alpha, const LVectorType& x, RVectorType& b) const
         {
-            LVectorType temp(lowRankFactor_.N());
-            lowRankFactor_.mv(x,temp);
+            LVectorType temp(lowRankFactor_->N());
+            lowRankFactor_->mv(x,temp);
 
-            typename LowRankFactorType::RowIterator row_end = lowRankFactor_.end();
-            typename LowRankFactorType::RowIterator row_it = lowRankFactor_.begin();
+            typename LowRankFactorType::ConstRowIterator row_end = lowRankFactor_->end();
+            typename LowRankFactorType::ConstRowIterator row_it = lowRankFactor_->begin();
             for (; row_it!=row_end; ++row_it)
             {
-                typename LowRankFactorType::ColIterator col_end = row_it->end();
-                typename LowRankFactorType::ColIterator col_it = row_it->begin();
+                typename LowRankFactorType::ConstColIterator col_end = row_it->end();
+                typename LowRankFactorType::ConstColIterator col_it = row_it->begin();
                 for (; col_it!=col_end; ++col_it)
-                    lowRankFactor_[row_it.index()][col_it.index()].usmv(alpha,temp[row_it.index()],b[col_it.index()]);
+                    (*lowRankFactor_)[row_it.index()][col_it.index()].usmv(alpha,temp[row_it.index()],b[col_it.index()]);
+            }
+        }
+
+        //! b -= Ax
+        template <class LVectorType, class RVectorType>
+        void mmv(const LVectorType& x, RVectorType& b) const
+        {
+            LVectorType temp(lowRankFactor_->N());
+            lowRankFactor_->mv(x,temp);
+
+            typename LowRankFactorType::ConstRowIterator row_end = lowRankFactor_->end();
+            typename LowRankFactorType::ConstRowIterator row_it = lowRankFactor_->begin();
+            for (; row_it!=row_end; ++row_it)
+            {
+                typename LowRankFactorType::ConstColIterator col_end = row_it->end();
+                typename LowRankFactorType::ConstColIterator col_it = row_it->begin();
+                for (; col_it!=col_end; ++col_it)
+                    (*lowRankFactor_)[row_it.index()][col_it.index()].mmv(temp[row_it.index()],b[col_it.index()]);
             }
         }
 
@@ -71,26 +103,33 @@ class LowRankOperator
         }
 
         //! returns number of rows
-        size_type N()
+        const size_type N() const
         {
-            return lowRankFactor_.M();
+            return lowRankFactor_->M();
         }
 
         //! returns number of columns
-        size_type M()
+        const size_type M() const
         {
-            return lowRankFactor_.M();
+            return lowRankFactor_->M();
         }
 
         //! returns the defining factor
-        const LowRankFactorType& getLowRankFactor() const
+        const LowRankFactorType& lowRankFactor() const
         {
-            return lowRankFactor_;
+            return *lowRankFactor_;
         }
 
+        //! returns the defining factor
+        LowRankFactorType& lowRankFactor()
+        {
+            return *lowRankFactor_;
+        }
     private:
         //! the defining factor
-        LowRankFactorType& lowRankFactor_;
+        LowRankFactorType* lowRankFactor_;
+
+        const bool factor_allocated_internally_;
 
 };