-----Original Message----- From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Simonson, Lucanus J Sent: 19 March 2009 20:11 To: boost@lists.boost.org Subject: Re: [boost] [geometry] robustness approaches
Paul A. Bristow wrote:
I've been following this erudite discussion with interest and a modest degree of understanding.
But one thing seems clear to me - that any quality implementation is going to require at the very least 'big' ints and 'big' floats, and probably exact int and exact floats.
It would seem that we need tried and tested Boost license implementations - preferably before starting work on a complex geometry problem. No solution can be considered for Boost if it uses any restrictive-licensed components.
GMP is licensed under the LGPL. That's not such a bad license. I don't know why we need to bypass it with a free implementation. Even so I don't depend on gmp header files in my geometry library. Instead I allow the "big" type to be overridden by specializing a meta-function that looks it up. I don't need to depend on GMP header files in my library code to use GMP with my library in an application. There is, incidently, a boost multi-precision library under development. Brandon tried it out about a year ago. It is a tall order to get performance up to the level of GMP, which uses inline assembly and clever C++ tricks to eliminate unnecesary copying of the heavy number types.
I'm sure GMP and mfpr are good. But the license issue should be fully resolved before you/we get too far down the line? Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow@hetp.u-net.com