--- Dan Perry wrote:
I need some sort of compile time float type that supports multiplication and division. I found your comments on the gmane.comp.lib.boost.devel newsgroup via google but I can't access your mpl_math.zip file. Could you send me your source? Thanks.
The file has a new home. Go to <http://boost-sandbox.sourceforge.net/vault/>, look under the subdirectory "expaler", and download from there. Major issues: 1. The big_integral<> numeric "metatype" is still a compiler resource hog. If I could use list<> instead of vector<>, I may be able to make it more efficient. To do so, I would need to know how to iterate through two lists "concurrently" instead of one list at a time. Aleksey Gurtovoy, any pointers? 2. The most recently added numeric metafunctions, which are square_root<>, exponent<>, sine<>, cosine<>, arctangent<>, hypersine<>, and hypercosine<>, are either insufficiently tested or not tested at all. 3. The numeric_caster_rt facility probably needs a more appropriate name. It is untested with wrt boost::rational as the ResultType. It is also non-functional wrt complex_number<>, at least until I figure out how to use std::complex. 4. Documentation should be available in the next version. For now, the source code, examples, and test programs will have to suffice. Andy Little wrote:
Why not call this one mixed_number?
Okay, your suggested name changes have been applied. Also, except for big_integral<>, the NumberSign parameter is now removed. Examples: rational<int_<11>,integral_c<long,16> > rational_c<long,-9,5> mixed_number<long_<2>,int_<54>,integral_c<int,100> > mixed_number_c<int,0,-2,5> The following expressions are currently illegal: rational<int_<1>,int_<0> > rational_c<long,9,-5> mixed_number<long_<3>,int_<-1>,integral_c<int,2> > mixed_number_c<int,0,6,5> I'm currently debating with myself about whether to make aux::rational2mixed_number<> part of the public interface; and if so, whether to rename it to something more legible; or if not, whether mixed_number<> and mixed_number_c<> should take default parameters.
IMO the rational Concept should hold independent of the exact parameters. The types used for the parameters are a trade off between using small_ints and having a relatively quick compile with the possibility of everflow, as against big_integers with long compile (and posibly run) times.
Actually only the relationship between the concept and the implementation models was dependent on the parameter "metatypes". But I know what you meant, so don't worry about it.
However in a large number of cases a rational has known bounds, so an inbuilt int has ample range.
Yeah. It's when you try things like the square_root<> example program (included in the zip file) that the inbuilt range becomes not enough.
I am wondering if the more lazy implementation possible by moving away from integral constant expansion might improve matters. OTOH perhaps it will make matters worse. (I am no expert on 'lazy' programming...but it must have some benefit?)
I'll try to implement some lazy versions of both big_integral<> and the new numeric metafunctions in the next version.
It is merely one among several possible compile time types that Might be useful as parameters. Other possibilities are the aforementioned big_int and a complex, should One not try to make the thing generic as possible? I dont think anything is lost by it. Even if the helper functions like gcd and abs are not useful for this they may come in useful somewhere else.
I've reimplemented rational<> so that it accepts any numeric constants M and N for which modulus<M,N> is a valid expression. That should improve its genericity. Cromwell D. Enage __________________________________ Do you Yahoo!? Yahoo! Mail - Helps protect you from nasty viruses. http://promotions.yahoo.com/new_mail