Diff: src/Core/NumTraits.h
- Revision:
- 0:13a5d365ba16
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Core/NumTraits.h Thu Oct 13 04:07:23 2016 +0000
@@ -0,0 +1,150 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2006-2010 Benoit Jacob <jacob.benoit.1@gmail.com>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#ifndef EIGEN_NUMTRAITS_H
+#define EIGEN_NUMTRAITS_H
+
+namespace Eigen {
+
+/** \class NumTraits
+ * \ingroup Core_Module
+ *
+ * \brief Holds information about the various numeric (i.e. scalar) types allowed by Eigen.
+ *
+ * \param T the numeric type at hand
+ *
+ * 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
+ * is a typedef to \a U.
+ * \li A typedef \a 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 \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
+ * type, and to 0 otherwise.
+ * \li An enum value \a IsInteger. It is equal to \c 1 if \a T is an integer type such as \c int,
+ * and to \c 0 otherwise.
+ * \li Enum values ReadCost, AddCost and MulCost representing a rough estimate of the number of CPU cycles needed
+ * to by move / add / mul instructions respectively, assuming the data is already stored in CPU registers.
+ * Stay vague here. No need to do architecture-specific stuff.
+ * \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 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.
+ */
+
+template<typename T> struct GenericNumTraits
+{
+ enum {
+ IsInteger = std::numeric_limits<T>::is_integer,
+ IsSigned = std::numeric_limits<T>::is_signed,
+ IsComplex = 0,
+ RequireInitialization = internal::is_arithmetic<T>::value ? 0 : 1,
+ ReadCost = 1,
+ AddCost = 1,
+ MulCost = 1
+ };
+
+ typedef T Real;
+ typedef typename internal::conditional<
+ IsInteger,
+ typename internal::conditional<sizeof(T)<=2, float, double>::type,
+ T
+ >::type NonInteger;
+ typedef T Nested;
+
+ static inline Real epsilon() { return std::numeric_limits<T>::epsilon(); }
+ static inline Real dummy_precision()
+ {
+ // make sure to override this for floating-point types
+ return Real(0);
+ }
+ static inline T highest() { return (std::numeric_limits<T>::max)(); }
+ static inline T lowest() { return IsInteger ? (std::numeric_limits<T>::min)() : (-(std::numeric_limits<T>::max)()); }
+
+#ifdef EIGEN2_SUPPORT
+ enum {
+ HasFloatingPoint = !IsInteger
+ };
+ typedef NonInteger FloatingPoint;
+#endif
+};
+
+template<typename T> struct NumTraits : GenericNumTraits<T>
+{};
+
+template<> struct NumTraits<float>
+ : GenericNumTraits<float>
+{
+ static inline float dummy_precision() { return 1e-5f; }
+};
+
+template<> struct NumTraits<double> : GenericNumTraits<double>
+{
+ static inline double dummy_precision() { return 1e-12; }
+};
+
+template<> struct NumTraits<long double>
+ : GenericNumTraits<long double>
+{
+ static inline long double dummy_precision() { return 1e-15l; }
+};
+
+template<typename _Real> struct NumTraits<std::complex<_Real> >
+ : GenericNumTraits<std::complex<_Real> >
+{
+ typedef _Real Real;
+ enum {
+ IsComplex = 1,
+ RequireInitialization = NumTraits<_Real>::RequireInitialization,
+ ReadCost = 2 * NumTraits<_Real>::ReadCost,
+ AddCost = 2 * NumTraits<Real>::AddCost,
+ MulCost = 4 * NumTraits<Real>::MulCost + 2 * NumTraits<Real>::AddCost
+ };
+
+ static inline Real epsilon() { return NumTraits<Real>::epsilon(); }
+ static inline Real dummy_precision() { return NumTraits<Real>::dummy_precision(); }
+};
+
+template<typename Scalar, int Rows, int Cols, int Options, int MaxRows, int MaxCols>
+struct NumTraits<Array<Scalar, Rows, Cols, Options, MaxRows, MaxCols> >
+{
+ typedef Array<Scalar, Rows, Cols, Options, MaxRows, MaxCols> ArrayType;
+ typedef typename NumTraits<Scalar>::Real RealScalar;
+ typedef Array<RealScalar, Rows, Cols, Options, MaxRows, MaxCols> Real;
+ typedef typename NumTraits<Scalar>::NonInteger NonIntegerScalar;
+ typedef Array<NonIntegerScalar, Rows, Cols, Options, MaxRows, MaxCols> NonInteger;
+ typedef ArrayType & Nested;
+
+ enum {
+ IsComplex = NumTraits<Scalar>::IsComplex,
+ IsInteger = NumTraits<Scalar>::IsInteger,
+ IsSigned = NumTraits<Scalar>::IsSigned,
+ RequireInitialization = 1,
+ ReadCost = ArrayType::SizeAtCompileTime==Dynamic ? Dynamic : ArrayType::SizeAtCompileTime * NumTraits<Scalar>::ReadCost,
+ AddCost = ArrayType::SizeAtCompileTime==Dynamic ? Dynamic : ArrayType::SizeAtCompileTime * NumTraits<Scalar>::AddCost,
+ MulCost = ArrayType::SizeAtCompileTime==Dynamic ? Dynamic : ArrayType::SizeAtCompileTime * NumTraits<Scalar>::MulCost
+ };
+
+ static inline RealScalar epsilon() { return NumTraits<RealScalar>::epsilon(); }
+ static inline RealScalar dummy_precision() { return NumTraits<RealScalar>::dummy_precision(); }
+};
+
+} // end namespace Eigen
+
+#endif // EIGEN_NUMTRAITS_H
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