Chris@49: // Copyright (C) 2009-2010 NICTA (www.nicta.com.au)
Chris@49: // Copyright (C) 2009-2010 Conrad Sanderson
Chris@49: // 
Chris@49: // This Source Code Form is subject to the terms of the Mozilla Public
Chris@49: // License, v. 2.0. If a copy of the MPL was not distributed with this
Chris@49: // file, You can obtain one at http://mozilla.org/MPL/2.0/.
Chris@49: 
Chris@49: 
Chris@49: //! \addtogroup upgrade_val
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! upgrade_val is used to ensure an operation such as multiplication is possible between two types.
Chris@49: //! values are upgraded only where necessary.
Chris@49: 
Chris@49: template<typename T1, typename T2>
Chris@49: struct upgrade_val
Chris@49:   {
Chris@49:   typedef typename promote_type<T1,T2>::result T1_result;
Chris@49:   typedef typename promote_type<T1,T2>::result T2_result;
Chris@49:   
Chris@49:   arma_inline
Chris@49:   static
Chris@49:   typename promote_type<T1,T2>::result
Chris@49:   apply(const T1 x)
Chris@49:     {
Chris@49:     typedef typename promote_type<T1,T2>::result out_type;
Chris@49:     return out_type(x);
Chris@49:     }
Chris@49:   
Chris@49:   arma_inline
Chris@49:   static
Chris@49:   typename promote_type<T1,T2>::result
Chris@49:   apply(const T2 x)
Chris@49:     {
Chris@49:     typedef typename promote_type<T1,T2>::result out_type;
Chris@49:     return out_type(x);
Chris@49:     }
Chris@49:   
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: // template<>
Chris@49: template<typename T>
Chris@49: struct upgrade_val<T,T>
Chris@49:   {
Chris@49:   typedef T T1_result;
Chris@49:   typedef T T2_result;
Chris@49:   
Chris@49:   arma_inline static const T& apply(const T& x) { return x; }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: //! upgrade a type to allow multiplication with a complex type
Chris@49: //! e.g. the int in "int * complex<double>" is upgraded to a double
Chris@49: // template<>
Chris@49: template<typename T, typename T2>
Chris@49: struct upgrade_val< std::complex<T>, T2 >
Chris@49:   {
Chris@49:   typedef std::complex<T> T1_result;
Chris@49:   typedef T               T2_result;
Chris@49:   
Chris@49:   arma_inline static const std::complex<T>& apply(const std::complex<T>& x) { return x;    }
Chris@49:   arma_inline static       T                apply(const T2 x)               { return T(x); }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: // template<>
Chris@49: template<typename T1, typename T>
Chris@49: struct upgrade_val< T1, std::complex<T> >
Chris@49:   {
Chris@49:   typedef T               T1_result;
Chris@49:   typedef std::complex<T> T2_result;
Chris@49:   
Chris@49:   arma_inline static       T                apply(const T1 x)               { return T(x); }
Chris@49:   arma_inline static const std::complex<T>& apply(const std::complex<T>& x) { return x;    }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: //! ensure we don't lose precision when multiplying a complex number with a higher precision real number
Chris@49: template<>
Chris@49: struct upgrade_val< std::complex<float>, double >
Chris@49:   {
Chris@49:   typedef std::complex<double> T1_result;
Chris@49:   typedef double               T2_result;
Chris@49:   
Chris@49:   arma_inline static const std::complex<double> apply(const std::complex<float>& x) { return std::complex<double>(x); }
Chris@49:   arma_inline static       double               apply(const double x)               { return x; }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: template<>
Chris@49: struct upgrade_val< double, std::complex<float> >
Chris@49:   {
Chris@49:   typedef double              T1_result;
Chris@49:   typedef std::complex<float> T2_result;
Chris@49:   
Chris@49:   arma_inline static       double               apply(const double x)               { return x; }
Chris@49:   arma_inline static const std::complex<double> apply(const std::complex<float>& x) { return std::complex<double>(x); }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: //! ensure we don't lose precision when multiplying complex numbers with different underlying types
Chris@49: template<>
Chris@49: struct upgrade_val< std::complex<float>, std::complex<double> >
Chris@49:   {
Chris@49:   typedef std::complex<double> T1_result;
Chris@49:   typedef std::complex<double> T2_result;
Chris@49:   
Chris@49:   arma_inline static const std::complex<double>  apply(const std::complex<float>&  x) { return std::complex<double>(x); }
Chris@49:   arma_inline static const std::complex<double>& apply(const std::complex<double>& x) { return x; }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: template<>
Chris@49: struct upgrade_val< std::complex<double>, std::complex<float> >
Chris@49:   {
Chris@49:   typedef std::complex<double> T1_result;
Chris@49:   typedef std::complex<double> T2_result;
Chris@49:   
Chris@49:   arma_inline static const std::complex<double>& apply(const std::complex<double>& x) { return x; }
Chris@49:   arma_inline static const std::complex<double>  apply(const std::complex<float>&  x) { return std::complex<double>(x); }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: //! work around limitations in the complex class (at least as present in gcc 4.1 & 4.3)
Chris@49: template<>
Chris@49: struct upgrade_val< std::complex<double>, float >
Chris@49:   {
Chris@49:   typedef std::complex<double> T1_result;
Chris@49:   typedef double               T2_result;
Chris@49:   
Chris@49:   arma_inline static const std::complex<double>& apply(const std::complex<double>& x) { return x; }
Chris@49:   arma_inline static       double                apply(const float x)                 { return double(x); }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: template<>
Chris@49: struct upgrade_val< float, std::complex<double> >
Chris@49:   {
Chris@49:   typedef double               T1_result;
Chris@49:   typedef std::complex<double> T2_result;
Chris@49:   
Chris@49:   arma_inline static       double                apply(const float x)                 { return double(x); }
Chris@49:   arma_inline static const std::complex<double>& apply(const std::complex<double>& x) { return x; }
Chris@49:   };
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}