From ed048eccc89ffabdb0ca5f8d0a8af4b98cce0200 Mon Sep 17 00:00:00 2001
From: Guido Kanschat <dr.guido.kanschat@gmail.com>
Date: Fri, 8 Apr 2005 09:16:43 +0000
Subject: [PATCH] add filtering small values to LogStream

git-svn-id: https://svn.dealii.org/trunk@10425 0785d39b-7218-0410-832d-ea1e28bc413d
---
 deal.II/base/include/base/logstream.h | 43 +++++++++++++++++++++++++++
 deal.II/base/source/log.cc            |  9 +++++-
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/deal.II/base/include/base/logstream.h b/deal.II/base/include/base/logstream.h
index 1675f1a1b8..3faea5d3e9 100644
--- a/deal.II/base/include/base/logstream.h
+++ b/deal.II/base/include/base/logstream.h
@@ -182,6 +182,15 @@ class LogStream
 				      * parameter is returned.
 				      */
     bool log_time_differences (const bool flag);
+
+				     /**
+				      * Set a threshold for the
+				      * minimal absolute value of
+				      * double values. All numbers
+				      * with a smaller absolute value
+				      * will be printed as zero.
+				      */
+    void threshold_double(const double t);
     
 				     /**
 				      * Output a constant something
@@ -190,6 +199,18 @@ class LogStream
     template <typename T>
     LogStream & operator << (const T &t);
 
+				     /**
+				      * Output double precision
+				      * numbers through this
+				      * stream. This function
+				      * eliminates floating point
+				      * numbers smaller than
+				      * #double_threshold, which can
+				      * be changed using
+				      * threshold_double().
+				      */
+    LogStream & operator << (const double t);
+
 				     /**
 				      * Treat ostream
 				      * manipulators. This passes on
@@ -314,6 +335,12 @@ class LogStream
 				      */
     double last_time;
 
+				     /**
+				      * Threshold for printing double
+				      * values.
+				      */
+    double double_threshold;
+    
 				     /**
 				      * Original buffer of
 				      * <tt>std::cerr</tt>. We store
@@ -361,6 +388,22 @@ LogStream::operator<< (const T& t)
 
 
 
+inline
+LogStream &
+LogStream::operator<< (const double t)
+{
+				   // do the work that is common to
+				   // the two operator<< functions
+  if (std::fabs(t) > double_threshold)
+    print (t);
+  else
+    print('0');
+  
+  return *this;
+}
+
+
+
 inline
 LogStream &
 LogStream::operator<< (std::ostream& (*p) (std::ostream&))
diff --git a/deal.II/base/source/log.cc b/deal.II/base/source/log.cc
index c8b9e9da09..204220f1a0 100644
--- a/deal.II/base/source/log.cc
+++ b/deal.II/base/source/log.cc
@@ -50,7 +50,7 @@ LogStream::LogStream()
 		std_out(&std::cerr), file(0), was_endl(true),
 		std_depth(10000), file_depth(10000),
 		print_utime(false), diff_utime(false),
-		last_time (0.), old_cerr(0)
+		last_time (0.), double_threshold(0.), old_cerr(0)
 {
   prefixes.push("DEAL:");
   std_out->setf(std::ios::showpoint | std::ios::left);
@@ -148,6 +148,13 @@ LogStream::depth_file (const unsigned n)
 }
 
 
+void
+LogStream::threshold_double (const double t)
+{
+  double_threshold = t;
+}
+
+
 bool
 LogStream::log_execution_time (const bool flag)
 {
-- 
2.39.5