From: Paul A Bristow (pbristow_at_[hidden])
Date: 2008-06-04 12:04:37
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 A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539561830 & SMS, Mobile +44 7714 330204 & 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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