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Re: [Bug-gsl] Bug in sys/ldfrexp.c
From: |
Brian Gough |
Subject: |
Re: [Bug-gsl] Bug in sys/ldfrexp.c |
Date: |
Mon, 29 Oct 2007 21:37:43 +0000 |
User-agent: |
Wanderlust/2.14.0 (Africa) Emacs/22.1 Mule/5.0 (SAKAKI) |
At Sat, 27 Oct 2007 19:47:12 -0400,
Chris Mihelich wrote:
> I wish to report and correct the following bugs in sys/ldfrexp.c:
>
> (1) gsl_ldexp computes a power of 2 (p2) that may overflow or
> underflow even though the correct answer is representable;
> consequently the return value x * p2 may be spuriously zero or
> infinity.
>
> (2) gsl_frexp can hang (this is what bit me in the rear at work
> yesterday) if its call to gsl_ldexp spuriously returns zero or
> infinity as in (1). The first while loop divides infinity by 2.0 over
> and over and wonders why it doesn't get any smaller; the second while
> loop has an analogous problem with zero.
Thanks for the bug report and code. I will fix those problems for
the next release.
--
best regards,
Brian Gough
(GSL Maintainer)
Network Theory Ltd,
Commercial support for GSL --- http://www.network-theory.com/gsl/