From 4098052a2bf24de6ee359302df21e5736d4ae5ad Mon Sep 17 00:00:00 2001
From: kanschat <kanschat@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Mon, 26 Sep 2011 15:06:23 +0000
Subject: [PATCH] add SparsityPattern::row_position

git-svn-id: https://svn.dealii.org/trunk@24428 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/doc/news/changes.h                    |  8 +++++++
 .../include/deal.II/lac/sparsity_pattern.h    | 22 ++++++++++++++-----
 deal.II/source/lac/sparsity_pattern.cc        | 20 +++++++++++++++--
 3 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/deal.II/doc/news/changes.h b/deal.II/doc/news/changes.h
index 6ddd79ea74..de6bdb9ecc 100644
--- a/deal.II/doc/news/changes.h
+++ b/deal.II/doc/news/changes.h
@@ -324,6 +324,14 @@ and DoF handlers embedded in higher dimensional space have been added.
 <h3>Specific improvements</h3>
 
 <ol>
+
+<li> New: SparsityPattern::row_position() finds a column index in a row and returns
+its "local" index or numbers::invalid_unsigned_int.
+<br>
+(Guido Kanschat, 2011/09/26)
+
+<li> New: There is now a function GridTools::volume() computing the volume
+
 <li> New: The function Utilities::MPI::sum
 function can be used to compute the sum of values over a number of
 MPI processes without having to deal with the underlying MPI functions.
diff --git a/deal.II/include/deal.II/lac/sparsity_pattern.h b/deal.II/include/deal.II/lac/sparsity_pattern.h
index 16b404d949..79310ada6f 100644
--- a/deal.II/include/deal.II/lac/sparsity_pattern.h
+++ b/deal.II/include/deal.II/lac/sparsity_pattern.h
@@ -366,8 +366,8 @@ class SparsityPattern : public Subscriptor
     static const unsigned int invalid_entry = numbers::invalid_unsigned_int;
 
 /**
- * @name Functions generating and
- * filling a SparsityPattern.
+ * @name Construction and setup
+ * Constructors, destructor; functions initializing, copying and filling an object.
  */
 // @{
 				     /**
@@ -1124,6 +1124,19 @@ class SparsityPattern : public Subscriptor
     bool exists (const unsigned int i,
                  const unsigned int j) const;
 
+				     /**
+				      * The index of a global matrix
+				      * entry in its row.
+				      *
+				      * This function is analogous to
+				      * operator(), but it computes
+				      * the index not with respect to
+				      * the total field, but only with
+				      * respect to the row <tt>j</tt>.
+				      */
+    unsigned int row_position(const unsigned int i,
+			      const unsigned int j) const;
+    
 				     /**
 				      * Access to column number field.
 				      * Return the column number of
@@ -1256,7 +1269,6 @@ class SparsityPattern : public Subscriptor
 // @{
                                      /**
 				      * @deprecated
-				      *
 				      * This function is deprecated. Use
 				      * SparsityTools::partition instead.
 				      *
@@ -1320,7 +1332,7 @@ class SparsityPattern : public Subscriptor
 
 
 				     /**
-				      * This is kind of an expert mode. Get
+				      * @deprecated This is kind of an expert mode. Get
 				      * access to the rowstart array, but
 				      * read-only.
 				      *
@@ -1377,8 +1389,8 @@ class SparsityPattern : public Subscriptor
     inline const unsigned int * get_column_numbers () const;
     
     BOOST_SERIALIZATION_SPLIT_MEMBER()
-
 				     /** @addtogroup Exceptions
+				      * @name Exceptions
 				      * @{ */
 				     /**
 				      * You tried to add an element to
diff --git a/deal.II/source/lac/sparsity_pattern.cc b/deal.II/source/lac/sparsity_pattern.cc
index d1d09ed4a9..5a113cd699 100644
--- a/deal.II/source/lac/sparsity_pattern.cc
+++ b/deal.II/source/lac/sparsity_pattern.cc
@@ -794,8 +794,7 @@ SparsityPattern::add_entries (const unsigned int row,
 
 
 bool
-SparsityPattern::exists (const unsigned int i,
-			 const unsigned int j) const
+SparsityPattern::exists (const unsigned int i, const unsigned int j) const
 {
   Assert ((rowstart!=0) && (colnums!=0), ExcEmptyObject());
   Assert (i<rows, ExcIndexRange(i,0,rows));
@@ -811,6 +810,23 @@ SparsityPattern::exists (const unsigned int i,
 
 
 
+unsigned int
+SparsityPattern::row_position (const unsigned int i, const unsigned int j) const
+{
+  Assert ((rowstart!=0) && (colnums!=0), ExcEmptyObject());
+  Assert (i<rows, ExcIndexRange(i,0,rows));
+  Assert (j<cols, ExcIndexRange(j,0,cols));
+
+  for (unsigned int k=rowstart[i]; k<rowstart[i+1]; k++)
+    {
+				       // entry exists
+      if (colnums[k] == j) return k-rowstart[i];
+    }
+  return numbers::invalid_unsigned_int;
+}
+
+
+
 std::pair<unsigned int, unsigned int>
 SparsityPattern::matrix_position (const unsigned int global_index) const
 {
-- 
2.39.5