-----Original Message----- From: Boost [mailto:boost-bounces@lists.boost.org] On Behalf Of John Maddock Sent: Tuesday, November 05, 2013 4:53 PM To: boost@lists.boost.org Subject: Re: [boost] [multiprecision] Radix-2 typedef naming convention
Thank you for this astute observation. In fact, we already have a proposal for optional typedefs such as float32_t, float64_t, and float128_t. They are to be defined in the global and std namespaces, and they are to be placed in new headers
and <cstdfloat>, respectively. Why not name the new radix-2 multiprecision types as follows? * boost::multiprecision::cpp_bin_float_24 * boost::multiprecision::cpp_bin_float_53 * boost::multiprecision::cpp_bin_float_113 * and the one for octuple precision
Sorry but that doesn't really work either - up until now we have consistently used:
float_type_N
to mean "Floating point type with at least N decimal digits", this is used consistently not only in cpp_dec_float, but in binary floating point types such as mpfr_float and mpf_float where we have typedefs such as:
typedef something mpfr_float_50; typedef something mpfr_float_100;
Which each have enough binary digits to guarantee 50 and 100 decimal place precision respectively.
So cpp_bin_float follows this and also has:
typedef something cpp_bin_float_50; typedef something cpp_bin_float_100;
So bit counts have to use a different naming convention to avoid confusion.
How about:
cpp_bin_float_single; cpp_bin_float_double; cpp_bin_float_quad;
I'm not sure what these actually provide. Is cpp_bin_float_double the same as the current boost::multiprecision::float53_t and *emulates* std::float64_t which is true IEEE layout 64-bit double? whereas float_53_t has 53 significand but a much bigger exponent)? Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow@hetp.u-net.com