From 3b7647c083061e87a6590b96dc3253c316031296 Mon Sep 17 00:00:00 2001
From: kanschat <kanschat@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Mon, 24 Jun 2013 06:54:03 +0000
Subject: [PATCH] Allow for resorting of diagonal

git-svn-id: https://svn.dealii.org/trunk@29854 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/include/deal.II/lac/sparse_matrix.h | 57 +++++++++++++++------
 1 file changed, 40 insertions(+), 17 deletions(-)

diff --git a/deal.II/include/deal.II/lac/sparse_matrix.h b/deal.II/include/deal.II/lac/sparse_matrix.h
index 0419e4d371..5c3fe719a8 100644
--- a/deal.II/include/deal.II/lac/sparse_matrix.h
+++ b/deal.II/include/deal.II/lac/sparse_matrix.h
@@ -1476,13 +1476,18 @@ public:
 //@{
 
   /**
-   * Print the matrix to the given stream, using the format <tt>(row,column)
-   * value</tt>, i.e. one nonzero entry of the matrix per line. If @p across
-   * is true, print all entries on a single line, using the format
-   * row,column:value
+   * Print the matrix to the given stream, using the format
+   * <tt>(row,column) value</tt>, i.e. one nonzero entry of the matrix
+   * per line. If <tt>across</tt> is true, print all entries on a
+   * single line, using the format row,column:value.
+   *
+   * If the argument <tt>diagonal_first</tt> is true, diagonal
+   * elements of quadratic matrices are printed first in their row,
+   * corresponding to the internal storage scheme. If it is false, the
+   * elements in a row are written in ascending column order.
    */
   template <class STREAM>
-  void print (STREAM &out, bool across=false) const;
+  void print (STREAM &out, bool across=false, bool diagonal_first=true) const;
 
   /**
    * Print the matrix in the usual format, i.e. as a matrix and not as a list
@@ -2464,22 +2469,40 @@ SparseMatrix<number>::end (const size_type r)
 template <typename number>
 template <class STREAM>
 inline
-void SparseMatrix<number>::print (STREAM &out, bool across) const
+void SparseMatrix<number>::print (STREAM &out, bool across, bool diagonal_first) const
 {
   Assert (cols != 0, ExcNotInitialized());
   Assert (val != 0, ExcNotInitialized());
-
+  
+  bool hanging_diagonal = false;
+  number diagonal;
+  
+  for (size_type i=0; i<cols->rows; ++i)
+    for (size_type j=cols->rowstart[i]; j<cols->rowstart[i+1]; ++j)
+      {
+	if (!diagonal_first && i == cols->colnums[j])
+	  {
+	    diagonal = val[j];
+	    hanging_diagonal = true;
+	  }
+	else
+	  {
+	    if (hanging_diagonal && cols->colnums[j]>i)
+	      {
+		if (across)
+		  out << '(' << i << ',' << i << ") " << diagonal << std::endl;
+		else
+		  out << ' ' << i << ',' << i << ':' << diagonal;
+		hanging_diagonal = false;
+	      }
+	    if (across)
+	      out << ' ' << i << ',' << cols->colnums[j] << ':' << val[j];
+	    else
+	      out << "(" << i << "," << cols->colnums[j] << ") " << val[j] << std::endl;
+	  }
+      }
   if (across)
-    {
-      for (size_type i=0; i<cols->rows; ++i)
-        for (size_type j=cols->rowstart[i]; j<cols->rowstart[i+1]; ++j)
-          out << ' ' << i << ',' << cols->colnums[j] << ':' << val[j];
-      out << std::endl;
-    }
-  else
-    for (size_type i=0; i<cols->rows; ++i)
-      for (size_type j=cols->rowstart[i]; j<cols->rowstart[i+1]; ++j)
-        out << "(" << i << "," << cols->colnums[j] << ") " << val[j] << std::endl;
+    out << std::endl;
 }
 
 
-- 
2.39.5