diff options
| author | Gabriel Dos Reis <gdr@merlin.codesourcery.com> | 2001-11-01 11:00:57 +0000 |
|---|---|---|
| committer | Gabriel Dos Reis <gdr@gcc.gnu.org> | 2001-11-01 11:00:57 +0000 |
| commit | 3c4e7c50811511bb73db16d2838262e0355020ce (patch) | |
| tree | f5f15b1cbc246e5f797a5ca59135a14aa87f1ce8 | |
| parent | 9199347f9a503b2a80c9ea2e74763f5d10f040bd (diff) | |
| download | gcc-3c4e7c50811511bb73db16d2838262e0355020ce.zip gcc-3c4e7c50811511bb73db16d2838262e0355020ce.tar.gz gcc-3c4e7c50811511bb73db16d2838262e0355020ce.tar.bz2 | |
std_complex.h (_Norm_helper): New class template.
* include/bits/std_complex.h (_Norm_helper): New class template.
(norm): Tweak.
From-SVN: r46690
| -rw-r--r-- | libstdc++-v3/ChangeLog | 5 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/std_complex.h | 32 |
2 files changed, 35 insertions, 2 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index bf6780e..cafd3a0 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,8 @@ +2001-11-01 Gabriel Dos Reis <gdr@merlin.codesourcery.com> + + * include/bits/std_complex.h (_Norm_helper): New class template. + (norm): Tweak. + 2001-10-31 Benjamin Kosnik <bkoz@redhat.com> libstdc++/4749 diff --git a/libstdc++-v3/include/bits/std_complex.h b/libstdc++-v3/include/bits/std_complex.h index c9573b7..fcd8c4d 100644 --- a/libstdc++-v3/include/bits/std_complex.h +++ b/libstdc++-v3/include/bits/std_complex.h @@ -40,6 +40,7 @@ #pragma GCC system_header #include <bits/c++config.h> +#include <bits/cpp_type_traits.h> #include <bits/std_cmath.h> #include <bits/std_sstream.h> @@ -417,12 +418,39 @@ namespace std arg(const complex<_Tp>& __z) { return atan2(__z.imag(), __z.real()); } + // 26.2.7/5: norm(__z) returns the squared magintude of __z. + // As defined, norm() is -not- a norm is the common mathematical + // sens used in numerics. The helper class _Norm_helper<> tries to + // distinguish between builtin floating point and the rest, so as + // to deliver an answer as close as possible to the real value. + template<bool> + struct _Norm_helper + { + template<typename _Tp> + static inline _Tp _S_do_it(const complex<_Tp>& __z) + { + const _Tp __x = __z.real(); + const _Tp __y = __z.imag(); + return __x * __x + __y * __y; + } + }; + + template<> + struct _Norm_helper<true> + { + template<typename _Tp> + static inline _Tp _S_do_it(const complex<_Tp>& __z) + { + _Tp __res = abs(__z); + return __res * __res; + } + }; + template<typename _Tp> inline _Tp norm(const complex<_Tp>& __z) { - _Tp __res = abs(__z); - return __res * __res; + return _Norm_helper<__is_floating<_Tp>::_M_type>::_S_do_it(__z); } template<typename _Tp> |