Re: [boost] [review] Multiprecision review scheduled for June 8th - 17th, 2012

Subject: Re: [boost] [review] Multiprecision review scheduled for June 8th - 17th, 2012
From: John Maddock (boost.regex_at_[hidden])
Date: 2012-06-05 13:06:06

>> You can see them as a special case of rationals where the denominator is
>> always a power of 2, so they grow more slowly than rationals.
>>
>>  Off hand I know of no other library that implements such a beast?
>>>
>>
>> CGAL. If you want to evaluate exactly the sign of a polynomial of double,
>> your best bets are this or a sum-of-double representation, depending on 
>> the
>> degree.
>>
>
> I want to echo Marc's comment that algorithms and numeric types where you
> only perform ring operations are common in computational geometry. You can
> often bound the size of your expression tree (as a function of your 
> spatial
> dimension), hence bound the size of your rationals. It might be worth
> considering this application within the scope of (proposed)
> Boost.Multiprecision. Indeed, I've used a C++ implementation of Jonathan
> Shewchuck's exact arithmetic algorithms [1] for such purposes.
>
> [1] http://www.cs.cmu.edu/~quake/robust.html

OK, clearly it's not a field I'm familiar with - for that reason I'd prefer 
not to be the one to write a backend for that - or at least I would need 
some considerable help - but I see no real obstacles to supporting such a 
type providing you don't want the transcendental functions.  If someone were 
willing to be the guinea pig, then it might make a good test case for seeing 
how easy it is for someone other than me to extend the library?

John.