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

Subject: Re: [boost] [review] Multiprecision review scheduled for June 8th - 17th, 2012
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2012-06-05 13:13:30

On Tue, Jun 5, 2012 at 10:06 AM, John Maddock <boost.regex_at_[hidden]>wrote:

> 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?
>

This is something I would be willing to contribute but probably not until
after the formal review.

- Jeff