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Re: calculator thinks 12!! = 0
From: |
Eli Barzilay |
Subject: |
Re: calculator thinks 12!! = 0 |
Date: |
02 Jul 2007 21:35:47 -0400 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 |
Joe Wells <jbw@macs.hw.ac.uk> writes:
> Dear Emacs gurus,
>
> To reproduce the problem, type "M-x calculator RET 12 ! !". You will
> see the result "0".
>
> More reasonable behavior would be what calculator does on 171!, which
> is return "inf".
>
> Additional strange behavior can be found by calculating 11!!, which
> seems to run forever (or at least longer than I had the patience to
> wait).
>
> The same poor behaviors can be observed also in Emacs 21.4 with the
> "-q" command line option, so this is not a new bug and it does not
> appear to depend on my configuration.
The calculator's factorial is nothing too sophisticated... It was
mostly a proof of concept. Some of the things that you see are a
result of what you get with:
(truncate 479001600.0)
(the calculator catches the error and uses 0 instead). I have a fix
for that -- if someone tells me where to send a new version to, I'll
do that so it gets in.
--
((lambda (x) (x x)) (lambda (x) (x x))) Eli Barzilay:
http://www.barzilay.org/ Maze is Life!