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authorGravatar Benoit Steiner <benoit.steiner.goog@gmail.com>2016-10-05 18:48:55 -0700
committerGravatar Benoit Steiner <benoit.steiner.goog@gmail.com>2016-10-05 18:48:55 -0700
commit78b569f68540c5609388864bd805dcf21dd6a187 (patch)
tree0a5757bb11834d0109f99310f4493dfd63579901 /Eigen/src/Core/NumTraits.h
parent9c2b6c049be19fd4c571b0df537169d277b26291 (diff)
parent4387433acf9cd2eab3713349163cd1e8905b5854 (diff)
Merged latest updates from trunk
Diffstat (limited to 'Eigen/src/Core/NumTraits.h')
-rw-r--r--Eigen/src/Core/NumTraits.h98
1 files changed, 77 insertions, 21 deletions
diff --git a/Eigen/src/Core/NumTraits.h b/Eigen/src/Core/NumTraits.h
index e065fa714..dd61195bc 100644
--- a/Eigen/src/Core/NumTraits.h
+++ b/Eigen/src/Core/NumTraits.h
@@ -12,6 +12,37 @@
namespace Eigen {
+namespace internal {
+
+// default implementation of digits10(), based on numeric_limits if specialized,
+// 0 for integer types, and log10(epsilon()) otherwise.
+template< typename T,
+ bool use_numeric_limits = std::numeric_limits<T>::is_specialized,
+ bool is_integer = NumTraits<T>::IsInteger>
+struct default_digits10_impl
+{
+ static int run() { return std::numeric_limits<T>::digits10; }
+};
+
+template<typename T>
+struct default_digits10_impl<T,false,false> // Floating point
+{
+ static int run() {
+ using std::log10;
+ using std::ceil;
+ typedef typename NumTraits<T>::Real Real;
+ return int(ceil(-log10(NumTraits<Real>::epsilon())));
+ }
+};
+
+template<typename T>
+struct default_digits10_impl<T,false,true> // Integer
+{
+ static int run() { return 0; }
+};
+
+} // end namespace internal
+
/** \class NumTraits
* \ingroup Core_Module
*
@@ -22,14 +53,16 @@ namespace Eigen {
* This class stores enums, typedefs and static methods giving information about a numeric type.
*
* The provided data consists of:
- * \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
+ * \li A typedef \c Real, giving the "real part" type of \a T. If \a T is already real,
+ * then \c Real is just a typedef to \a T. If \a T is \c std::complex<U> then \c Real
* is a typedef to \a U.
- * \li A typedef \a NonInteger, giving the type that should be used for operations producing non-integral values,
+ * \li A typedef \c NonInteger, giving the type that should be used for operations producing non-integral values,
* such as quotients, square roots, etc. If \a T is a floating-point type, then this typedef just gives
* \a T again. Note however that many Eigen functions such as internal::sqrt simply refuse to
* take integers. Outside of a few cases, Eigen doesn't do automatic type promotion. Thus, this typedef is
* only intended as a helper for code that needs to explicitly promote types.
+ * \li A typedef \c Literal giving the type to use for numeric literals such as "2" or "0.5". For instance, for \c std::complex<U>, Literal is defined as \c U.
+ * Of course, this type must be fully compatible with \a T. In doubt, just use \a T here.
* \li A typedef \a Nested giving the type to use to nest a value inside of the expression tree. If you don't know what
* this means, just use \a T here.
* \li An enum value \a IsComplex. It is equal to 1 if \a T is a \c std::complex
@@ -42,10 +75,14 @@ namespace Eigen {
* \li An enum value \a IsSigned. It is equal to \c 1 if \a T is a signed type and to 0 if \a T is unsigned.
* \li An enum value \a RequireInitialization. It is equal to \c 1 if the constructor of the numeric type \a T must
* be called, and to 0 if it is safe not to call it. Default is 0 if \a T is an arithmetic type, and 1 otherwise.
- * \li An epsilon() function which, unlike std::numeric_limits::epsilon(), returns a \a Real instead of a \a T.
+ * \li An epsilon() function which, unlike <a href="http://en.cppreference.com/w/cpp/types/numeric_limits/epsilon">std::numeric_limits::epsilon()</a>,
+ * it returns a \a Real instead of a \a T.
* \li A dummy_precision() function returning a weak epsilon value. It is mainly used as a default
* value by the fuzzy comparison operators.
* \li highest() and lowest() functions returning the highest and lowest possible values respectively.
+ * \li digits10() function returning the number of decimal digits that can be represented without change. This is
+ * the analogue of <a href="http://en.cppreference.com/w/cpp/types/numeric_limits/digits10">std::numeric_limits<T>::digits10</a>
+ * which is used as the default implementation if specialized.
*/
template<typename T> struct GenericNumTraits
@@ -60,23 +97,6 @@ template<typename T> struct GenericNumTraits
MulCost = 1
};
- // Division is messy but important, because it is expensive and throughput
- // varies significantly. The following numbers are based on min division
- // throughput on Haswell.
- template<bool Vectorized>
- struct Div {
- enum {
-#ifdef EIGEN_VECTORIZE_AVX
- AVX = true,
-#else
- AVX = false,
-#endif
- Cost = IsInteger ? (sizeof(T) == 8 ? (IsSigned ? 24 : 21) : (IsSigned ? 8 : 9)):
- Vectorized ? (sizeof(T) == 8 ? (AVX ? 16 : 8) : (AVX ? 14 : 7)) : 8
- };
- };
-
-
typedef T Real;
typedef typename internal::conditional<
IsInteger,
@@ -84,12 +104,20 @@ template<typename T> struct GenericNumTraits
T
>::type NonInteger;
typedef T Nested;
+ typedef T Literal;
EIGEN_DEVICE_FUNC
static inline Real epsilon()
{
return numext::numeric_limits<T>::epsilon();
}
+
+ EIGEN_DEVICE_FUNC
+ static inline int digits10()
+ {
+ return internal::default_digits10_impl<T>::run();
+ }
+
EIGEN_DEVICE_FUNC
static inline Real dummy_precision()
{
@@ -145,6 +173,7 @@ template<typename _Real> struct NumTraits<std::complex<_Real> >
: GenericNumTraits<std::complex<_Real> >
{
typedef _Real Real;
+ typedef typename NumTraits<_Real>::Literal Literal;
enum {
IsComplex = 1,
RequireInitialization = NumTraits<_Real>::RequireInitialization,
@@ -157,6 +186,8 @@ template<typename _Real> struct NumTraits<std::complex<_Real> >
static inline Real epsilon() { return NumTraits<Real>::epsilon(); }
EIGEN_DEVICE_FUNC
static inline Real dummy_precision() { return NumTraits<Real>::dummy_precision(); }
+ EIGEN_DEVICE_FUNC
+ static inline int digits10() { return NumTraits<Real>::digits10(); }
};
template<typename Scalar, int Rows, int Cols, int Options, int MaxRows, int MaxCols>
@@ -168,6 +199,7 @@ struct NumTraits<Array<Scalar, Rows, Cols, Options, MaxRows, MaxCols> >
typedef typename NumTraits<Scalar>::NonInteger NonIntegerScalar;
typedef Array<NonIntegerScalar, Rows, Cols, Options, MaxRows, MaxCols> NonInteger;
typedef ArrayType & Nested;
+ typedef typename NumTraits<Scalar>::Literal Literal;
enum {
IsComplex = NumTraits<Scalar>::IsComplex,
@@ -185,6 +217,30 @@ struct NumTraits<Array<Scalar, Rows, Cols, Options, MaxRows, MaxCols> >
static inline RealScalar dummy_precision() { return NumTraits<RealScalar>::dummy_precision(); }
};
+template<> struct NumTraits<std::string>
+ : GenericNumTraits<std::string>
+{
+ enum {
+ RequireInitialization = 1,
+ ReadCost = HugeCost,
+ AddCost = HugeCost,
+ MulCost = HugeCost
+ };
+
+ static inline int digits10() { return 0; }
+
+private:
+ static inline std::string epsilon();
+ static inline std::string dummy_precision();
+ static inline std::string lowest();
+ static inline std::string highest();
+ static inline std::string infinity();
+ static inline std::string quiet_NaN();
+};
+
+// Empty specialization for void to allow template specialization based on NumTraits<T>::Real with T==void and SFINAE.
+template<> struct NumTraits<void> {};
+
} // end namespace Eigen
#endif // EIGEN_NUMTRAITS_H