Re: [boost] Rounding, Truncating Values

From: Hervé Brönnimann (hervebronnimann_at_[hidden])
Date: 2008-06-04 22:43:05

I can perhaps offer some help designing the interface, but I'm having  
way more fun at programming myself than mentoring.  Which is a  
convoluted way to say I'm too busy and would decline (at this time)  
mentoring any such project.  If someone else was mentoring and needed  
a sounding board for discussion, I'd have good resonance, though :)
--
Hervé Brönnimann
hervebronnimann_at_[hidden]
On Jun 4, 2008, at 12:04 PM, Paul A Bristow wrote:
> Perhaps we can suggest it for GSoC next year?  I'll try to remember  
> to do that - but your supervision/mentoring will be invaluable.
>
> I vaguely recall that an unlimited precision integer would be  
> needed? Or was it just a big/whopper integer? This would be valuable
> as a Boost thingy anyway?
>
> Paul
>
> ---
> Paul A Bristow
> Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB
> [phone] & SMS, Mobile [phone] & SMS
> pbristow_at_[hidden]
>
>
>
>> -----Original Message-----
>> From: boost-bounces_at_[hidden]
>> [mailto:boost-bounces_at_[hidden]] On Behalf Of Hervé Brönnimann
>> Sent: 04 June 2008 06:12
>> To: boost_at_[hidden]
>> Subject: Re: [boost] Rounding, Truncating Values
>>
>> Paul:  Most valuable indeed.  Like a bullion of gold, because in
>> practice they aren't much slower than the run-of-the-mill sscanf/
>> sprintf (a few extra cycles, except once in a while in spurious
>> boundary cases where you need more than one or two extra binary
>> digits).  But the guaranteed round-trip, and extra precision, is well
>> worth it.  But who's got the time... <insert here great
>> proselytization about boost, library code, reuse, etc.> :)
>>
>> Oh, I remember fondly implementing Bellerophon in grad school
>> (Clinger's original scanf).  We had two weeks in Dave Hanson's
>> systems programming class, 40% of the grade for the code working on
>> the given examples, 40% for working on his test suite -- which he
>> *didn't* give us access to, and 20% for the style/doc.  In 13 weeks,
>> we worked 13 problems (two weeks each, one week to research/read and
>> discuss during the next class, overlapping with implementing the
>> previous project).  Projects ranged from various SIGPLAN/research
>> recent or classical articles illustrating systems issues, e.g. this
>> (floating point), impl. a context switcher for Solaris threads in
>> assembler, impl. a symbolic tree manip for optimization (Dave gave us
>> his lcc compiler, we only tweaked the optimizing module), some new/
>> improved graph algorithm for manipulating symbols in a linker's
>> symbol table, a couple of hard optimization problems (with
>> heuristics), incl. some speach audio data analysis, etc.  You get the
>> idea.
>>
>> Dave's class was the best programming class I ever took, and one I
>> hope to teach again myself someday.  If any teacher/instructor is
>> listening, this is a formula I most highly recommend.  Keeps everyone
>> honest, and teaches discipline like nothing else.  (Lots of work for
>> the teacher though; Dave had set up a black-box server wherein we
>> could test our program, and output had to be *identical*, a la ACM
>> Competition; grading was automatic by running private test suite and
>> diff'ing the outputs.)
>>
>> I got Bellerophon to work all right, it isn't that hard if you follow
>> the math (not a small feat, though), but it requires meticulous
>> implementation skills (and will beat it into you if you don't have
>> it).  Then begins the fun with infinities and nans...  and for
>> dessert: subnormal numbers.
>>
>> Either one (both?) would be a great SoC project, by the way, if any
>> student is listening, once you have the right interface.
>> --
>> Hervé Brönnimann
>> hervebronnimann_at_[hidden]
>>
>>
>> On Jun 3, 2008, at 10:59 AM, Paul A Bristow wrote:
>>
>>>
>>> I've glanced at the Burger and Dybvig algorithms you quote, but
>>> they don't seem too simple to implement.  If any one can get they to
>>> work, they would be most valuable.
>
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