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armadillo-code/include/armadillo_bits/arma_cmath.hpp
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2020-12-05 13:11:17 +10:00

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// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------
//! \addtogroup arma_cmath
//! @{
//
// wrappers for isfinite
template<typename eT>
arma_inline
bool
arma_isfinite(eT val)
{
arma_ignore(val);
return true;
}
template<>
arma_inline
bool
arma_isfinite(float x)
{
#if defined(ARMA_USE_CXX11)
{
return std::isfinite(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::isfinite(x);
}
#elif defined(ARMA_HAVE_ISFINITE)
{
return (std::isfinite(x) != 0);
}
#else
{
const float y = (std::numeric_limits<float>::max)();
const volatile float xx = x;
return (xx == xx) && (x >= -y) && (x <= y);
}
#endif
}
template<>
arma_inline
bool
arma_isfinite(double x)
{
#if defined(ARMA_USE_CXX11)
{
return std::isfinite(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::isfinite(x);
}
#elif defined(ARMA_HAVE_ISFINITE)
{
return (std::isfinite(x) != 0);
}
#else
{
const double y = (std::numeric_limits<double>::max)();
const volatile double xx = x;
return (xx == xx) && (x >= -y) && (x <= y);
}
#endif
}
template<typename T>
arma_inline
bool
arma_isfinite(const std::complex<T>& x)
{
if( (arma_isfinite(x.real()) == false) || (arma_isfinite(x.imag()) == false) )
{
return false;
}
else
{
return true;
}
}
//
// wrappers for isinf
template<typename eT>
arma_inline
bool
arma_isinf(eT val)
{
arma_ignore(val);
return false;
}
template<>
arma_inline
bool
arma_isinf(float x)
{
#if defined(ARMA_USE_CXX11)
{
return std::isinf(x);
}
#elif defined(ARMA_HAVE_ISINF)
{
return (std::isinf(x) != 0);
}
#else
{
const float y = (std::numeric_limits<float>::max)();
const volatile float xx = x;
return (xx == xx) && ((x < -y) || (x > y));
}
#endif
}
template<>
arma_inline
bool
arma_isinf(double x)
{
#if defined(ARMA_USE_CXX11)
{
return std::isinf(x);
}
#elif defined(ARMA_HAVE_ISINF)
{
return (std::isinf(x) != 0);
}
#else
{
const double y = (std::numeric_limits<double>::max)();
const volatile double xx = x;
return (xx == xx) && ((x < -y) || (x > y));
}
#endif
}
template<typename T>
arma_inline
bool
arma_isinf(const std::complex<T>& x)
{
return ( arma_isinf(x.real()) || arma_isinf(x.imag()) );
}
//
// wrappers for isnan
template<typename eT>
arma_inline
bool
arma_isnan(eT val)
{
arma_ignore(val);
return false;
}
template<>
arma_inline
bool
arma_isnan(float x)
{
#if defined(ARMA_USE_CXX11)
{
return std::isnan(x);
}
#elif defined(ARMA_HAVE_ISNAN)
{
return (std::isnan(x) != 0);
}
#else
{
const volatile float xx = x;
return (xx != xx);
}
#endif
}
template<>
arma_inline
bool
arma_isnan(double x)
{
#if defined(ARMA_USE_CXX11)
{
return std::isnan(x);
}
#elif defined(ARMA_HAVE_ISNAN)
{
return (std::isnan(x) != 0);
}
#else
{
const volatile double xx = x;
return (xx != xx);
}
#endif
}
template<typename T>
arma_inline
bool
arma_isnan(const std::complex<T>& x)
{
return ( arma_isnan(x.real()) || arma_isnan(x.imag()) );
}
// rudimentary wrappers for log1p()
arma_inline
float
arma_log1p(const float x)
{
#if defined(ARMA_USE_CXX11)
{
return std::log1p(x);
}
#else
{
if((x >= float(0)) && (x < std::numeric_limits<float>::epsilon()))
{
return x;
}
else
if((x < float(0)) && (-x < std::numeric_limits<float>::epsilon()))
{
return x;
}
else
{
return std::log(float(1) + x);
}
}
#endif
}
arma_inline
double
arma_log1p(const double x)
{
#if defined(ARMA_USE_CXX11)
{
return std::log1p(x);
}
#elif defined(ARMA_HAVE_LOG1P)
{
return log1p(x);
}
#else
{
if((x >= double(0)) && (x < std::numeric_limits<double>::epsilon()))
{
return x;
}
else
if((x < double(0)) && (-x < std::numeric_limits<double>::epsilon()))
{
return x;
}
else
{
return std::log(double(1) + x);
}
}
#endif
}
//
// implementation of arma_sign()
template<typename eT>
arma_inline
typename arma_unsigned_integral_only<eT>::result
arma_sign(const eT x)
{
return (x > eT(0)) ? eT(+1) : eT(0);
}
template<typename eT>
arma_inline
typename arma_signed_integral_only<eT>::result
arma_sign(const eT x)
{
return (x > eT(0)) ? eT(+1) : ( (x < eT(0)) ? eT(-1) : eT(0) );
}
template<typename eT>
arma_inline
typename arma_real_only<eT>::result
arma_sign(const eT x)
{
return (x > eT(0)) ? eT(+1) : ( (x < eT(0)) ? eT(-1) : ((x == eT(0)) ? eT(0) : x) );
}
template<typename eT>
arma_inline
typename arma_cx_only<eT>::result
arma_sign(const eT& x)
{
typedef typename eT::value_type T;
const T abs_x = std::abs(x);
return (abs_x != T(0)) ? (x / abs_x) : x;
}
//
// wrappers for trigonometric functions
//
// wherever possible, try to use C++11 or TR1 versions of the following functions:
//
// complex acos
// complex asin
// complex atan
//
// real acosh
// real asinh
// real atanh
//
// complex acosh
// complex asinh
// complex atanh
//
//
// if C++11 or TR1 are not available, we have rudimentary versions of:
//
// real acosh
// real asinh
// real atanh
template<typename T>
arma_inline
std::complex<T>
arma_acos(const std::complex<T>& x)
{
#if defined(ARMA_USE_CXX11)
{
return std::acos(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::acos(x);
}
#else
{
arma_ignore(x);
arma_stop_logic_error("acos(): C++11 compiler required");
return std::complex<T>(0);
}
#endif
}
template<typename T>
arma_inline
std::complex<T>
arma_asin(const std::complex<T>& x)
{
#if defined(ARMA_USE_CXX11)
{
return std::asin(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::asin(x);
}
#else
{
arma_ignore(x);
arma_stop_logic_error("asin(): C++11 compiler required");
return std::complex<T>(0);
}
#endif
}
template<typename T>
arma_inline
std::complex<T>
arma_atan(const std::complex<T>& x)
{
#if defined(ARMA_USE_CXX11)
{
return std::atan(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::atan(x);
}
#else
{
arma_ignore(x);
arma_stop_logic_error("atan(): C++11 compiler required");
return std::complex<T>(0);
}
#endif
}
template<typename eT>
arma_inline
eT
arma_acosh(const eT x)
{
#if defined(ARMA_USE_CXX11)
{
return std::acosh(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::acosh(x);
}
#else
{
if(x >= eT(1))
{
// http://functions.wolfram.com/ElementaryFunctions/ArcCosh/02/
return std::log( x + std::sqrt(x*x - eT(1)) );
}
else
{
if(std::numeric_limits<eT>::has_quiet_NaN)
{
return -(std::numeric_limits<eT>::quiet_NaN());
}
else
{
return eT(0);
}
}
}
#endif
}
template<typename eT>
arma_inline
eT
arma_asinh(const eT x)
{
#if defined(ARMA_USE_CXX11)
{
return std::asinh(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::asinh(x);
}
#else
{
// http://functions.wolfram.com/ElementaryFunctions/ArcSinh/02/
return std::log( x + std::sqrt(x*x + eT(1)) );
}
#endif
}
template<typename eT>
arma_inline
eT
arma_atanh(const eT x)
{
#if defined(ARMA_USE_CXX11)
{
return std::atanh(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::atanh(x);
}
#else
{
if( (x >= eT(-1)) && (x <= eT(+1)) )
{
// http://functions.wolfram.com/ElementaryFunctions/ArcTanh/02/
return std::log( ( eT(1)+x ) / ( eT(1)-x ) ) / eT(2);
}
else
{
if(std::numeric_limits<eT>::has_quiet_NaN)
{
return -(std::numeric_limits<eT>::quiet_NaN());
}
else
{
return eT(0);
}
}
}
#endif
}
template<typename T>
arma_inline
std::complex<T>
arma_acosh(const std::complex<T>& x)
{
#if defined(ARMA_USE_CXX11)
{
return std::acosh(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::acosh(x);
}
#else
{
arma_ignore(x);
arma_stop_logic_error("acosh(): C++11 compiler required");
return std::complex<T>(0);
}
#endif
}
template<typename T>
arma_inline
std::complex<T>
arma_asinh(const std::complex<T>& x)
{
#if defined(ARMA_USE_CXX11)
{
return std::asinh(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::asinh(x);
}
#else
{
arma_ignore(x);
arma_stop_logic_error("asinh(): C++11 compiler required");
return std::complex<T>(0);
}
#endif
}
template<typename T>
arma_inline
std::complex<T>
arma_atanh(const std::complex<T>& x)
{
#if defined(ARMA_USE_CXX11)
{
return std::atanh(x);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::atanh(x);
}
#else
{
arma_ignore(x);
arma_stop_logic_error("atanh(): C++11 compiler required");
return std::complex<T>(0);
}
#endif
}
//
// wrappers for hypot(x, y) = sqrt(x^2 + y^2)
template<typename eT>
inline
eT
arma_hypot_generic(const eT x, const eT y)
{
#if defined(ARMA_USE_CXX11)
{
return std::hypot(x, y);
}
#elif defined(ARMA_HAVE_TR1)
{
return std::tr1::hypot(x, y);
}
#else
{
const eT xabs = std::abs(x);
const eT yabs = std::abs(y);
eT larger;
eT ratio;
if(xabs > yabs)
{
larger = xabs;
ratio = yabs / xabs;
}
else
{
larger = yabs;
ratio = xabs / yabs;
}
return (larger == eT(0)) ? eT(0) : (larger * std::sqrt(eT(1) + ratio * ratio));
}
#endif
}
template<typename eT>
inline
eT
arma_hypot(const eT x, const eT y)
{
arma_ignore(x);
arma_ignore(y);
arma_stop_runtime_error("arma_hypot(): not implemented for integer or complex element types");
return eT(0);
}
template<>
arma_inline
float
arma_hypot(const float x, const float y)
{
return arma_hypot_generic(x,y);
}
template<>
arma_inline
double
arma_hypot(const double x, const double y)
{
return arma_hypot_generic(x,y);
}
//
// implementation of arma_sinc()
template<typename eT>
arma_inline
eT
arma_sinc_generic(const eT x)
{
typedef typename get_pod_type<eT>::result T;
const eT tmp = Datum<T>::pi * x;
return (tmp == eT(0)) ? eT(1) : eT( std::sin(tmp) / tmp );
}
template<typename eT>
arma_inline
eT
arma_sinc(const eT x)
{
return eT( arma_sinc_generic( double(x) ) );
}
template<>
arma_inline
float
arma_sinc(const float x)
{
return arma_sinc_generic(x);
}
template<>
arma_inline
double
arma_sinc(const double x)
{
return arma_sinc_generic(x);
}
template<typename T>
arma_inline
std::complex<T>
arma_sinc(const std::complex<T>& x)
{
return arma_sinc_generic(x);
}
//
// wrappers for arg()
template<typename eT>
struct arma_arg
{
static
inline
eT
eval(const eT x)
{
#if defined(ARMA_USE_CXX11)
{
return eT( std::arg(x) );
}
#else
{
arma_ignore(x);
arma_stop_logic_error("arg(): C++11 compiler required");
return eT(0);
}
#endif
}
};
template<>
struct arma_arg<float>
{
static
arma_inline
float
eval(const float x)
{
#if defined(ARMA_USE_CXX11)
{
return std::arg(x);
}
#else
{
return std::arg( std::complex<float>( x, float(0) ) );
}
#endif
}
};
template<>
struct arma_arg<double>
{
static
arma_inline
double
eval(const double x)
{
#if defined(ARMA_USE_CXX11)
{
return std::arg(x);
}
#else
{
return std::arg( std::complex<double>( x, double(0) ) );
}
#endif
}
};
template<>
struct arma_arg< std::complex<float> >
{
static
arma_inline
float
eval(const std::complex<float>& x)
{
return std::arg(x);
}
};
template<>
struct arma_arg< std::complex<double> >
{
static
arma_inline
double
eval(const std::complex<double>& x)
{
return std::arg(x);
}
};
//! @}