From 53031e6ce5a321d37b5bdb47b5eb46643380ea29 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@math.tamu.edu>
Date: Thu, 9 Aug 2001 12:46:50 +0000
Subject: [PATCH] Provide BlockVector with a new constructor that initializes
 the vector from an iterator range.

git-svn-id: https://svn.dealii.org/trunk@4872 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/doc/news/2001/c-3-1.html              |  3 +-
 deal.II/lac/include/lac/block_vector.h        | 52 +++++++++++++++++++
 .../lac/include/lac/block_vector.templates.h  |  2 +-
 tests/lac/block_vector.cc                     | 22 ++++++++
 tests/lac/block_vector.checked                |  2 +
 5 files changed, 79 insertions(+), 2 deletions(-)

diff --git a/deal.II/doc/news/2001/c-3-1.html b/deal.II/doc/news/2001/c-3-1.html
index ee4dc6318a..e7726ec5cd 100644
--- a/deal.II/doc/news/2001/c-3-1.html
+++ b/deal.II/doc/news/2001/c-3-1.html
@@ -333,7 +333,8 @@ documentation, etc</a>.
 
 <ol>
   <li> <p>
-       Changed: The <code class="class">Vector</code> class can now be
+       Changed: The <code class="class">Vector</code> and
+       <code class="class">BlockVector</code> classes can now be
        initialized using a new constructor that takes two iterators
        that denote a range of elements which are to be copied.
        <br>
diff --git a/deal.II/lac/include/lac/block_vector.h b/deal.II/lac/include/lac/block_vector.h
index 5ef51077eb..cf3742122d 100644
--- a/deal.II/lac/include/lac/block_vector.h
+++ b/deal.II/lac/include/lac/block_vector.h
@@ -125,6 +125,29 @@ class BlockVector
 				      */
     BlockVector (const std::vector<unsigned int> &n);
 
+				     /**
+				      * Constructor. Set the number of
+				      * blocks to
+				      * @p{n.size()}. Initialize the
+				      * vector with the elements
+				      * pointed to by the range of
+				      * iterators given as second and
+				      * third argument. Apart from the
+				      * first argument, this
+				      * constructor is in complete
+				      * analogy to the respective
+				      * constructor of the
+				      * @p{std::vector} class, but the
+				      * first argument is needed in
+				      * order to know how to subdivide
+				      * the block vector into
+				      * different blocks.
+				      */
+    template <typename InputIterator>
+    BlockVector (const std::vector<unsigned int> &n,
+		 const InputIterator              first,
+		 const InputIterator              end);
+    
                                      /**
 				      * Destructor. Clears memory
 				      */
@@ -486,6 +509,11 @@ class BlockVector
 
 				     //@}
 
+				     /**
+				      * Exception
+				      */
+    DeclException0 (ExcIteratorRangeDoesNotMatchVectorSize);
+
   protected:
 				     /**
 				      * Pointer to the array of components.
@@ -514,6 +542,30 @@ class BlockVector
 /*----------------------- Inline functions ----------------------------------*/
 
 
+template <typename Number>
+template <typename InputIterator>
+BlockVector<Number>::BlockVector (const std::vector<unsigned int> &n,
+				  const InputIterator              first,
+				  const InputIterator              end)
+{
+				   // first set sizes of blocks, but
+				   // don't initialize them as we will
+				   // copy elements soon
+  reinit (n, true);
+  InputIterator start = first;
+  for (unsigned int b=0; b<n.size(); ++b)
+    {
+      InputIterator end = start;
+      std::advance (end, static_cast<signed int>(n[b]));
+      std::copy (start, end, block(b).begin());
+      start = end;
+    };
+  Assert (start == end, ExcIteratorRangeDoesNotMatchVectorSize());
+};
+
+
+
+
 template <typename Number>
 inline
 unsigned int BlockVector<Number>::size () const
diff --git a/deal.II/lac/include/lac/block_vector.templates.h b/deal.II/lac/include/lac/block_vector.templates.h
index a5aafd99ab..68af1979db 100644
--- a/deal.II/lac/include/lac/block_vector.templates.h
+++ b/deal.II/lac/include/lac/block_vector.templates.h
@@ -73,7 +73,7 @@ BlockVector<Number>::BlockVector (const BlockVector<Number>& v)
 template <typename Number>
 void BlockVector<Number>::reinit (const unsigned int n_bl,
 				  const unsigned int bl_sz,
-				  const bool                  fast)
+				  const bool         fast)
 {
   std::vector<unsigned int> n(n_bl, bl_sz);
   reinit(n, fast);
diff --git a/tests/lac/block_vector.cc b/tests/lac/block_vector.cc
index 618f55ebc1..f884d024cc 100644
--- a/tests/lac/block_vector.cc
+++ b/tests/lac/block_vector.cc
@@ -18,6 +18,7 @@
 #include <lac/block_vector.h>
 #include <fstream>
 #include <vector>
+#include <list>
 
 void test ()
 {
@@ -43,6 +44,27 @@ void test ()
 	    << std::endl;
   deallog.pop();
 
+
+				   // initialization by an iterator
+				   // range
+  deallog.push ("Initialization from iterators");
+  double array[] = { 0, 1, 2, 3, 4, 5 };
+  BlockVector<double> v1(ivector, &array[0], &array[6]);
+  for (unsigned int i=0; i<v1.size(); ++i)
+    deallog << v1(i) << ' ';
+  deallog << std::endl;
+
+				   // same test, but do not initialize
+				   // from double*'s, but from
+				   // std::list iterators.
+  std::list<double> l(&array[0], &array[6]);
+  BlockVector<double> v2(ivector, l.begin(), l.end());
+  for (unsigned int i=0; i<v2.size(); ++i)
+    deallog << v2(i) << ' ';
+  deallog << std::endl;
+  deallog.pop ();
+
+  
   i3.reinit(ivector);
 
   deallog.push("global->local");
diff --git a/tests/lac/block_vector.checked b/tests/lac/block_vector.checked
index 811f688b14..a0081f9b9d 100644
--- a/tests/lac/block_vector.checked
+++ b/tests/lac/block_vector.checked
@@ -1,4 +1,6 @@
 
+DEAL:BlockIndices:Initialization from iterators::0.000 1.000 2.000 3.000 4.000 5.000 
+DEAL:BlockIndices:Initialization from iterators::0.000 1.000 2.000 3.000 4.000 5.000 
 DEAL:BlockIndices:global->local::0	0	0	0	0	0	0
 DEAL:BlockIndices:global->local::1	0	1	0	1	0	1
 DEAL:BlockIndices:global->local::2	0	2	0	2	0	2
-- 
2.39.5