Re: [boost] GGL Review

Subject: Re: [boost] GGL Review
From: Jonathan Franklin (franklin.jonathan_at_[hidden])
Date: 2009-11-17 12:47:24

On Tue, Nov 17, 2009 at 10:23 AM, Phil Endecott
<spam_from_boost_dev_at_[hidden]> wrote:
> Do please have a look at the paper that I linked to before, and in
> particular the figure at the top of the second page:
>
>  http://www.mpi-inf.mpg.de/~kettner/pub/nonrobust_cgta_06.pdf

I have read this, and several other papers.  I've even taken a few
numerical analysis classes at the university.

> 1. Failures may not occur only in cases when things are very close.  A
> problematic input may cause the output to be grossly wrong.

Lady luck has smiled on me thus far.
;-)

And a small amount of data pre-processing goes a *long* way.  Know
your algorithms, and their pre/post-conditions.

> 2. You may not get a wrong answer; the program might instead segfault or
> loop forever.

This is not a FP-induced instability problem.  This is a bug in your
algorithm.  Coincidentally, I just fixed a loop-forever bug in one of
our geometry algorithms the other day.

Jon