From 98ce68e2afdced05a8cc7364b88f2eace9184ef2 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@math.tamu.edu>
Date: Tue, 25 Apr 2006 21:31:24 +0000
Subject: [PATCH] BlockSparsityPattern::row_length.

git-svn-id: https://svn.dealii.org/trunk@12896 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/doc/news/changes.html                 |  9 +++++++
 .../lac/include/lac/block_sparsity_pattern.h  | 27 +++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/deal.II/doc/news/changes.html b/deal.II/doc/news/changes.html
index dd02cde18d..3ae3abe42c 100644
--- a/deal.II/doc/news/changes.html
+++ b/deal.II/doc/news/changes.html
@@ -442,6 +442,15 @@ inconvenience this causes.
 
 <ol>
   
+  <li> <p> New: The function <code
+       class="member">BlockSparsityPattern::row_length</code> adds up
+       the row lengths of the individual blocks of a block matrix for
+       a given row.
+       <br> 
+       (WB 2006/04/25)
+       </p>
+
+  
   <li> <p> New: There is a new class <code
        class="class">IdentityMatrix</code> that represents an
        efficient version of the matrix with ones on the diagonal and
diff --git a/deal.II/lac/include/lac/block_sparsity_pattern.h b/deal.II/lac/include/lac/block_sparsity_pattern.h
index 1a4613068e..a537e9ebe5 100644
--- a/deal.II/lac/include/lac/block_sparsity_pattern.h
+++ b/deal.II/lac/include/lac/block_sparsity_pattern.h
@@ -294,6 +294,14 @@ class BlockSparsityPatternBase : public Subscriptor
 				      * position may be non-zero.
 				      */
     bool exists (const unsigned int i, const unsigned int j) const;
+
+				     /**
+				      * Number of entries in a
+				      * specific row, added up over
+				      * all the blocks that form this
+				      * row.
+				      */
+    unsigned int row_length (const unsigned int row) const;
     
 				     /**
 				      * Return the number of nonzero
@@ -615,6 +623,25 @@ BlockSparsityPatternBase<SparsityPatternBase>::exists (const unsigned int i,
 
 
 
+template <class SparsityPatternBase>
+inline
+unsigned int
+BlockSparsityPatternBase<SparsityPatternBase>::
+row_length (const unsigned int row) const
+{
+  const std::pair<unsigned int,unsigned int>
+    row_index = row_indices.global_to_local (row);
+
+  unsigned int c = 0;
+  
+  for (unsigned int b=0; b<rows; ++b)
+    c += sub_objects[row_index.first][b]->row_length (row_index.second);
+
+  return c;
+}
+
+
+
 template <class SparsityPatternBase>
 inline
 unsigned int
-- 
2.39.5