From a753650709daf364e2a48b1e710650436cd1a1e0 Mon Sep 17 00:00:00 2001
From: kronbichler <kronbichler@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Wed, 7 Jan 2009 15:03:00 +0000
Subject: [PATCH] Some more functions in TrilinosWrappers::SparsityPattern.

git-svn-id: https://svn.dealii.org/trunk@18118 0785d39b-7218-0410-832d-ea1e28bc413d
---
 .../include/lac/trilinos_sparsity_pattern.h   | 42 ++++++++++++++++-
 .../lac/source/trilinos_sparsity_pattern.cc   | 47 +++++++++++++++++++
 2 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/deal.II/lac/include/lac/trilinos_sparsity_pattern.h b/deal.II/lac/include/lac/trilinos_sparsity_pattern.h
index 3ef763066d..7bab1edc20 100755
--- a/deal.II/lac/include/lac/trilinos_sparsity_pattern.h
+++ b/deal.II/lac/include/lac/trilinos_sparsity_pattern.h
@@ -750,6 +750,19 @@ namespace TrilinosWrappers
                                         */
       unsigned int row_length (const unsigned int row) const;
 
+                                       /**
+					* Compute the bandwidth of the
+					* matrix represented by this
+					* structure. The bandwidth is the
+					* maximum of $|i-j|$ for which the
+					* index pair $(i,j)$ represents a
+					* nonzero entry of the
+					* matrix. Consequently, the maximum
+					* bandwidth a $n\times m$ matrix can
+					* have is $\max\{n-1,m-1\}$.
+                                        */
+      unsigned int bandwidth () const;
+
                                        /**
                                         * Return whether the object is
                                         * empty. It is empty if no memory is
@@ -860,13 +873,40 @@ namespace TrilinosWrappers
 					* implemented.
 					*/
       void write_ascii ();
-      
+
 				       /**
 					* Print the sparsity pattern to the
 					* given stream, using the format
 					* <tt>(line,col)</tt>.
 					*/
       void print (std::ostream &out) const;
+
+				       /**
+					* Print the sparsity of the matrix
+					* in a format that <tt>gnuplot</tt>
+					* understands and which can be used
+					* to plot the sparsity pattern in a
+					* graphical way. The format consists
+					* of pairs <tt>i j</tt> of nonzero
+					* elements, each representing one
+					* entry of this matrix, one per line
+					* of the output file. Indices are
+					* counted from zero on, as
+					* usual. Since sparsity patterns are
+					* printed in the same way as
+					* matrices are displayed, we print
+					* the negative of the column index,
+					* which means that the
+					* <tt>(0,0)</tt> element is in the
+					* top left rather than in the bottom
+					* left corner.
+					*
+					* Print the sparsity pattern in
+					* gnuplot by setting the data style
+					* to dots or points and use the
+					* <tt>plot</tt> command.
+					*/
+      void print_gnuplot (std::ostream &out) const;
     
                                         // TODO: Write an overloading
                                         // of the operator << for output.
diff --git a/deal.II/lac/source/trilinos_sparsity_pattern.cc b/deal.II/lac/source/trilinos_sparsity_pattern.cc
index 3a1379ea0b..5b5fdaacfa 100755
--- a/deal.II/lac/source/trilinos_sparsity_pattern.cc
+++ b/deal.II/lac/source/trilinos_sparsity_pattern.cc
@@ -616,6 +616,28 @@ namespace TrilinosWrappers
 
 
 
+  unsigned int
+  SparsityPattern::bandwidth () const
+  {
+    unsigned int local_b=0;
+    int global_b=0;
+    for (unsigned int i=0; i<local_size(); ++i)
+      {
+	int * indices;
+	int num_entries;
+	graph->ExtractMyRowView(i, num_entries, indices);
+	for (unsigned int j=0; j<(unsigned int)num_entries; ++j)
+	  {
+	    if (static_cast<unsigned int>(std::abs(static_cast<int>(i-indices[j]))) > local_b)
+	      local_b = std::abs(static_cast<signed int>(i-indices[j]));
+	  }
+      }
+    graph->Comm().MaxAll((int *)&local_b, &global_b, 1);
+    return static_cast<unsigned int>(global_b);
+  }
+
+
+
   unsigned int
   SparsityPattern::n_rows () const
   {
@@ -732,6 +754,31 @@ namespace TrilinosWrappers
 
 
 
+  void
+  SparsityPattern::print_gnuplot (std::ostream &out) const
+  { 
+    Assert (graph->Filled() == true, ExcInternalError());
+    for (unsigned int row=0; row<local_size(); ++row)
+      {
+	signed int * indices;
+	int num_entries;
+	graph->ExtractMyRowView (row, num_entries, indices);
+
+	for (unsigned int j=0; j<(unsigned int)num_entries; ++j)
+                                         // while matrix entries are usually
+                                         // written (i,j), with i vertical and
+                                         // j horizontal, gnuplot output is
+                                         // x-y, that is we have to exchange
+                                         // the order of output
+	  out << indices[graph->GRID(j)] << " " << -static_cast<signed int>(row) 
+	      << std::endl;
+      }      
+
+    AssertThrow (out, ExcIO());
+  }
+
+
+
 
   // explicit instantiations
   //
-- 
2.39.5