eigen/src/Core/Numeric.h

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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2006-2007 Benoit Jacob <jacob@math.jussieu.fr>
//
// Eigen is free software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the Free Software
// Foundation; either version 2 or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
// details.
//
// You should have received a copy of the GNU General Public License along
// with Eigen; if not, write to the Free Software Foundation, Inc., 51
// Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. This exception does not invalidate any other reasons why a work
// based on this file might be covered by the GNU General Public License.
#ifndef EI_NUMERIC_H
#define EI_NUMERIC_H
template<typename T> struct EiNumTraits;
template<> struct EiNumTraits<int>
{
typedef int Real;
typedef double FloatingPoint;
typedef double RealFloatingPoint;
static const bool IsComplex = false;
static const bool HasFloatingPoint = false;
static int epsilon() { return 0; }
static int real(const int& x) { return x; }
static int imag(const int& x) { EI_UNUSED(x); return 0; }
static int conj(const int& x) { return x; }
static double sqrt(const int& x) { return std::sqrt(static_cast<double>(x)); }
static int abs(const int& x) { return std::abs(x); }
static int abs2(const int& x) { return x*x; }
static int rand()
{
// "rand()%21" would be bad. always use the high-order bits, not the low-order bits.
// note: here (gcc 4.1) static_cast<int> seems to round the nearest int.
// I don't know if that's part of the standard.
return -10 + static_cast<int>(std::rand() / ((RAND_MAX + 1.0)/20.0));
}
};
template<> struct EiNumTraits<float>
{
typedef float Real;
typedef float FloatingPoint;
typedef float RealFloatingPoint;
static const bool IsComplex = false;
static const bool HasFloatingPoint = true;
static float epsilon() { return 1e-5f; }
static float real(const float& x) { return x; }
static float imag(const float& x) { EI_UNUSED(x); return 0; }
static float conj(const float& x) { return x; }
static float sqrt(const float& x) { return std::sqrt(x); }
static float abs(const float& x) { return std::abs(x); }
static float abs2(const float& x) { return x*x; }
static float rand()
{
return std::rand() / (RAND_MAX/20.0f) - 10.0f;
}
};
template<> struct EiNumTraits<double>
{
typedef double Real;
typedef double FloatingPoint;
typedef double RealFloatingPoint;
static const bool IsComplex = false;
static const bool HasFloatingPoint = true;
static double epsilon() { return 1e-11; }
static double real(const double& x) { return x; }
static double imag(const double& x) { EI_UNUSED(x); return 0; }
static double conj(const double& x) { return x; }
static double sqrt(const double& x) { return std::sqrt(x); }
static double abs(const double& x) { return std::abs(x); }
static double abs2(const double& x) { return x*x; }
static double rand()
{
return std::rand() / (RAND_MAX/20.0) - 10.0;
}
};
template<typename _Real> struct EiNumTraits<std::complex<_Real> >
{
typedef _Real Real;
typedef std::complex<Real> Complex;
typedef std::complex<double> FloatingPoint;
typedef typename EiNumTraits<Real>::FloatingPoint RealFloatingPoint;
static const bool IsComplex = true;
static const bool HasFloatingPoint = EiNumTraits<Real>::HasFloatingPoint;
static Real epsilon() { return EiNumTraits<Real>::epsilon(); }
static Real real(const Complex& x) { return std::real(x); }
static Real imag(const Complex& x) { return std::imag(x); }
static Complex conj(const Complex& x) { return std::conj(x); }
static FloatingPoint sqrt(const Complex& x)
{ return std::sqrt(static_cast<FloatingPoint>(x)); }
static RealFloatingPoint abs(const Complex& x)
{ return std::abs(static_cast<FloatingPoint>(x)); }
static Real abs2(const Complex& x)
{ return std::real(x) * std::real(x) + std::imag(x) * std::imag(x); }
static Complex rand()
{
return Complex(EiNumTraits<Real>::rand(), EiNumTraits<Real>::rand());
}
};
template<typename T> typename EiNumTraits<T>::Real EiReal(const T& x)
{ return EiNumTraits<T>::real(x); }
template<typename T> typename EiNumTraits<T>::Real EiImag(const T& x)
{ return EiNumTraits<T>::imag(x); }
template<typename T> T EiConj(const T& x)
{ return EiNumTraits<T>::conj(x); }
template<typename T> typename EiNumTraits<T>::FloatingPoint EiSqrt(const T& x)
{ return EiNumTraits<T>::sqrt(x); }
template<typename T> typename EiNumTraits<T>::RealFloatingPoint EiAbs(const T& x)
{ return EiNumTraits<T>::abs(x); }
template<typename T> typename EiNumTraits<T>::Real EiAbs2(const T& x)
{ return EiNumTraits<T>::abs2(x); }
template<typename T> T EiRand()
{ return EiNumTraits<T>::rand(); }
template<typename T> bool EiNegligible(const T& a, const T& b)
{
return(EiAbs(a) <= EiAbs(b) * EiNumTraits<T>::epsilon());
}
template<typename T> bool EiApprox(const T& a, const T& b)
{
if(EiNumTraits<T>::IsFloat)
return(EiAbs(a - b) <= std::min(EiAbs(a), EiAbs(b)) * EiNumTraits<T>::epsilon());
else
return(a == b);
}
template<typename T> bool EiLessThanOrApprox(const T& a, const T& b)
{
if(EiNumTraits<T>::IsFloat)
return(a < b || EiApprox(a, b));
else
return(a <= b);
}
#endif // EI_NUMERIC_H