[R] Logical inconsistency

Berwin A Turlach berwin at maths.uwa.edu.au
Mon Dec 8 13:51:08 CET 2008

G'day Wacek,

On Mon, 08 Dec 2008 13:13:33 +0100
Wacek Kusnierczyk <Waclaw.Marcin.Kusnierczyk at idi.ntnu.no> wrote:

> Berwin A Turlach wrote:
> >
> > I am not surprised about CS guys never learning about these
> > issues.  As long as you play around with data bases (their
> > organisation &c), sorting algorithms, artificial intelligence (at
> > least when I attended a lecture on this) you do not need to know
> > about these issues.  And, unfortunately, it seems nowadays a lot of
> > teaching is on a "need-to-know" and "just-in-time" basis.  
> >
> > It just became criminal when CS guys who were into compiler design
> > started to construct compilers that analysed the code and rearranged
> > the calculations based on an analysis that assumed infinite
> > precision arithmetic.  Such compilers optimised away code that was
> > designed to deal with finite precision arithmetic.  I believe this
> > was one of the motivations of Goldberg's article.
> >
> >   
> you'd probably enjoy hacker's delight by warren [1], where tricks are
> presented that allow you to use computer arithmetic efficiently when
> you know the details of the representations.

Unlikely, these days I am less interested in hacks but more in portable
implementations.  If it were to show that somethings I believe to be
portable are actually not, then it could be of interest after all.



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