From 15acb63eb306f37235fedc3128c2334e462f84ef Mon Sep 17 00:00:00 2001
From: Michael Hemmer <hemmer@mpi-inf.mpg.de>
Date: Sun, 28 Jun 2009 13:10:48 +0000
Subject: [PATCH] semantic change change default of .compare: now expecting
 that two numbers are from the same extension added CGAL::compare with analog
 interface, added test, updated documentation This is more consistent with all
 compare operators which expect the same anyway. This change should increase
 the performace of related code considerably.

---
 .../NumberTypeSupport_ref/Sqrt_extension.tex  |  2 +-
 .../CGAL/Sqrt_extension/Sqrt_extension_type.h | 13 +++++--
 .../test/Number_types/Sqrt_extension.cpp      | 36 +++++++++++++++++++
 3 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/Number_types/doc_tex/NumberTypeSupport_ref/Sqrt_extension.tex b/Number_types/doc_tex/NumberTypeSupport_ref/Sqrt_extension.tex
index 6a33954c33b..da322c6b147 100644
--- a/Number_types/doc_tex/NumberTypeSupport_ref/Sqrt_extension.tex
+++ b/Number_types/doc_tex/NumberTypeSupport_ref/Sqrt_extension.tex
@@ -143,7 +143,7 @@ $a0 + a1 * sqrt(root)$.
 
 \ccMethod{
 Sqrt_extension compare 
-(const Sqrt_extension& y, bool in_same_extension = false) const;}{
+(const Sqrt_extension& y, bool in_same_extension = true) const;}{
   Compares \ccVar\ with y. \\
   The optional bool \ccc{in_same_extension} indicates whether \ccVar\ 
   and $y$ are in the same extension of NT.
diff --git a/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h b/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
index 72c646b327a..86bb1943709 100644
--- a/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
+++ b/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
@@ -422,9 +422,11 @@ compare (const NT& num) const {
     return ((Self(a0_ - num, a1_, root_)).sign_());
 }
 
-// compare of two values with different extension
+// compare of two values that may be in different extension
+// However, the default is, that the the numbers are defined over the same
+// extension. 
 CGAL::Comparison_result
-compare(const Self& y, bool in_same_extension = false ) const
+compare(const Self& y, bool in_same_extension = true ) const
 {
     if (! is_extended_)
         return (CGAL::opposite (y.compare (a0_)));
@@ -619,6 +621,13 @@ const Sqrt_extension<NT,ROOT> & y){
   return (std::max)(x,y);
 }
 
+template <class NT, class ROOT> inline 
+CGAL::Comparison_result compare (
+    const Sqrt_extension<NT,ROOT>& x, 
+    const Sqrt_extension<NT,ROOT>& y,
+    bool in_same_extension = true ){
+  return x.compare(y,in_same_extension);
+}
 
 CGAL_END_NAMESPACE
 
diff --git a/Number_types/test/Number_types/Sqrt_extension.cpp b/Number_types/test/Number_types/Sqrt_extension.cpp
index 86f58c8d595..104afa64b6b 100644
--- a/Number_types/test/Number_types/Sqrt_extension.cpp
+++ b/Number_types/test/Number_types/Sqrt_extension.cpp
@@ -339,6 +339,38 @@ void to_double_test(){
         assert(to_interval(ext)==CGAL_NTS to_interval(-3.0) );
     }
 }
+
+//This test is dedicated to the comaprison of numbers from different extensions
+template <class EXT>
+void test_compare(){
+  typedef typename EXT::NT NT;
+  typedef typename EXT::ROOT ROOT;
+
+  EXT a(NT(1),NT(-5),ROOT(7));
+  EXT b(NT(2),NT(8),ROOT(5));
+  EXT c(NT(3),NT(0),ROOT(3));
+  
+  assert(a.compare(b,false)==CGAL::SMALLER);
+  assert(a.compare(c,false)==CGAL::SMALLER);
+  assert(b.compare(c,false)==CGAL::LARGER );
+  assert(a.compare(a,false)==CGAL::EQUAL);
+  assert(b.compare(b,false)==CGAL::EQUAL);
+  assert(c.compare(c,false)==CGAL::EQUAL);
+  assert(a.compare(a,true)==CGAL::EQUAL);
+  assert(b.compare(b,true)==CGAL::EQUAL);
+  assert(c.compare(c,true)==CGAL::EQUAL);
+
+  assert(CGAL::compare(a,b,false)==CGAL::SMALLER);
+  assert(CGAL::compare(a,c,false)==CGAL::SMALLER);
+  assert(CGAL::compare(b,c,false)==CGAL::LARGER );
+  assert(CGAL::compare(a,a,false)==CGAL::EQUAL);
+  assert(CGAL::compare(b,b,false)==CGAL::EQUAL);
+  assert(CGAL::compare(c,c,false)==CGAL::EQUAL);
+  assert(CGAL::compare(a,a,true)==CGAL::EQUAL);
+  assert(CGAL::compare(b,b,true)==CGAL::EQUAL);
+  assert(CGAL::compare(c,c,true)==CGAL::EQUAL);
+}
+
 template <class NT, class ROOT, class Algebraic_type>
 void general_test(){
     typedef typename CGAL::Algebraic_structure_traits<NT>::Is_exact Is_exact; 
@@ -379,6 +411,10 @@ void general_test(){
     io_test<EXT3>();  
    
     to_double_test<EXT1>();
+    
+    test_compare<EXT1>();
+    test_compare<EXT2>();
+    test_compare<EXT3>();
 }