Re: [boost] [MPL.Math] updates for double

From: Cromwell Enage (sponage_at_[hidden])
Date: 2005-11-10 11:10:28

--- Peder Holt wrote:
> I have a series available that converges for X>1.
> I'll implement it once the pi<> template is ready.

I just learned that when a compiler sees a plain
struct or a full specialization inherit from an MPL
expression, it eagerly evaluates the expression,
whehter or not the program actually asks for the
struct/specialization.  This is fine for
pi<double_tag>, but bad news for pi<rational_tag> and
pi<mixed_number_tag>, because I don't yet have a
generic way of representing 1/5 and 1/239 -- Hmmm. 
Maybe I should implement an inverse metafunction. 
Yeah, that'll solve this particular problem.

> Btw. How about making the syntax a bit clearer by
> dropping the BOOST_PP_MUL etc. syntax? Why not just:
> 
>         typedef typename minus< \
>                     int_<1> \
>                   , times< \
>                         divides< \
>                             angle_squared \
>                           , int_< \
>                                 (\
>                                    
> (BOOST_MPL_LIMIT_MATH_SINE_SERIES-x)*2+1\
>                                 )*\
>                                 (\
>                                    
> (BOOST_MPL_LIMIT_MATH_SINE_SERIES-x)*2\
>                                 )\
>                             >\
>                         > \
>                       , BOOST_PP_CAT(prefix, x) \
>                     > \
>                 >::type \
> 
> I think this is more readable, and less limited
> (BOOST_PP_MUL(129,2) exceeds 256, not that it
> matters much, as we should never have this long
> series :)

Will do.

> Have uploaded a version of tangent that uses the
> preprocessor, plus a version of arcus_sine and an
> alternative arcus_tangent that does not :) to the
> vault.

Okay, I'll check them out.

                              Cromwell D. Enage

        
                
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