From bb290977b8e4ec43dbd1f628e357d762da0e33d5 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Wed, 10 Feb 2010 11:11:21 +0100
Subject: [PATCH] add highest and lowest functions to NumTraits

---
 Eigen/src/Core/NumTraits.h | 38 ++++++++++++++++++++++++++------------
 1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/Eigen/src/Core/NumTraits.h b/Eigen/src/Core/NumTraits.h
index 7279e156d..f4036dc0c 100644
--- a/Eigen/src/Core/NumTraits.h
+++ b/Eigen/src/Core/NumTraits.h
@@ -34,7 +34,7 @@
   *          \c std::complex<float>, \c std::complex<double>, and \c long \c double (especially
   *          useful to enforce x87 arithmetics when SSE is the default).
   *
-  * The provided data consists of:
+  * The provided data consists of everything that is supported by std::numeric_limits, plus:
   * \li A typedef \a Real, giving the "real part" type of \a T. If \a T is already real,
   *     then \a Real is just a typedef to \a T. If \a T is \c std::complex<U> then \a Real
   *     is a typedef to \a U.
@@ -45,11 +45,29 @@
   *     type, and to 0 otherwise.
   * \li An enum \a HasFloatingPoint. It is equal to \c 0 if \a T is \c int,
   *     and to \c 1 otherwise.
+  * \li An epsilon() function which, unlike std::numeric_limits::epsilon(), returns a \a Real instead of a \a T.
+  * \li A dummy_precision() function returning a weak epsilon value. It is mainly used by the fuzzy comparison operators.
+  * \li Two higest() and lowest() functions returning the higest and lowest possible values respectively.
   */
 template<typename T> struct NumTraits;
 
+template<typename T> struct ei_default_float_numtraits
+  : std::numeric_limits<T>
+{
+  inline static T higest() { return  std::numeric_limits<T>::max(); }
+  inline static T lowest() { return -std::numeric_limits<T>::max(); }
+};
+
+template<typename T> struct ei_default_integral_numtraits
+  : std::numeric_limits<T>
+{
+  inline static int dummy_precision() { return 0; }
+  inline static T highest() { return std::numeric_limits<T>::max(); }
+  inline static T lowest()  { return std::numeric_limits<T>::min(); }
+};
+
 template<> struct NumTraits<int>
-  : std::numeric_limits<int>
+  : ei_default_integral_numtraits<int>
 {
   typedef int Real;
   typedef double FloatingPoint;
@@ -61,12 +79,10 @@ template<> struct NumTraits<int>
     AddCost = 1,
     MulCost = 1
   };
-
-  inline static int dummy_precision() { return 0; }
 };
 
 template<> struct NumTraits<float>
-  : std::numeric_limits<float>
+  : ei_default_float_numtraits<float>
 {
   typedef float Real;
   typedef float FloatingPoint;
@@ -83,7 +99,7 @@ template<> struct NumTraits<float>
 };
 
 template<> struct NumTraits<double>
-  : std::numeric_limits<double>
+  : ei_default_float_numtraits<double>
 {
   typedef double Real;
   typedef double FloatingPoint;
@@ -100,7 +116,7 @@ template<> struct NumTraits<double>
 };
 
 template<typename _Real> struct NumTraits<std::complex<_Real> >
-  : std::numeric_limits<std::complex<_Real> >
+  : ei_default_float_numtraits<std::complex<_Real> >
 {
   typedef _Real Real;
   typedef std::complex<_Real> FloatingPoint;
@@ -118,7 +134,7 @@ template<typename _Real> struct NumTraits<std::complex<_Real> >
 };
 
 template<> struct NumTraits<long long int>
-  : std::numeric_limits<long long int>
+  : ei_default_integral_numtraits<long long int>
 {
   typedef long long int Real;
   typedef long double FloatingPoint;
@@ -133,7 +149,7 @@ template<> struct NumTraits<long long int>
 };
 
 template<> struct NumTraits<long double>
-  : std::numeric_limits<long double>
+  : ei_default_float_numtraits<long double>
 {
   typedef long double Real;
   typedef long double FloatingPoint;
@@ -150,7 +166,7 @@ template<> struct NumTraits<long double>
 };
 
 template<> struct NumTraits<bool>
-  : std::numeric_limits<bool>
+  : ei_default_integral_numtraits<bool>
 {
   typedef bool Real;
   typedef float FloatingPoint;
@@ -162,8 +178,6 @@ template<> struct NumTraits<bool>
     AddCost = 1,
     MulCost = 1
   };
-
-  inline static bool dummy_precision() { return 0; }
 };
 
 #endif // EIGEN_NUMTRAITS_H