From: Jean Louis <bugs@gnu.support>
To: Teemu Likonen <tlikonen@iki.fi>
Cc: help-gnu-emacs@gnu.org, Stefan Monnier <monnier@iro.umontreal.ca>
Subject: Re: What is 0.01 here not 0.01 here 0.009999999999999?
Date: Fri, 2 Apr 2021 21:44:40 +0300 [thread overview]
Message-ID: <YGdmGLIeMiFY5gWJ@protected.localdomain> (raw)
In-Reply-To: <87eefsk2hq.fsf@iki.fi>
* Teemu Likonen <tlikonen@iki.fi> [2021-04-02 20:42]:
> * 2021-04-02 20:03:54+0300, Jean Louis wrote:
>
> > Not that I need the absolute internally, just the practical
> > result as we learned it in school like that 10.11 plus 0.01
> > results with 10.12 and not something else. Results are used for
> > automated version numbers (in some cases).
>
> As you have learned, floating point numbers are not decimal numbers even
> if they are read and printed as such. For decimal mathematics you can
> use calc-eval function. Some comparison:
>
> ELISP> (+ 10.12 0.01)
> 10.129999999999999
>
> ELISP> (calc-eval "10.12 + 0.01")
> "10.13"
>
> ELISP> (* 3 0.1)
> 0.30000000000000004
>
> ELISP> (calc-eval "3 * 0.1")
> "0.3"
Hey, that is good to know, it spares me efforts.
--
Jean
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next prev parent reply other threads:[~2021-04-02 18:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-02 13:42 What is 0.01 here not 0.01 here 0.009999999999999? Jean Louis
2021-04-02 13:56 ` Stefan Monnier
2021-04-02 17:03 ` Jean Louis
2021-04-02 17:41 ` Teemu Likonen
2021-04-02 18:44 ` Jean Louis [this message]
2021-04-02 20:46 ` John Yates
2021-04-02 21:19 ` Jean Louis
2021-04-02 22:04 ` John Yates
2021-04-02 23:29 ` Jean Louis
2021-04-03 4:39 ` Arthur Miller
2021-04-03 5:36 ` Jean Louis
2021-04-03 3:56 ` Arthur Miller
2021-04-03 5:19 ` Jean Louis
2021-04-03 13:54 ` Stefan Monnier
2021-04-02 14:02 ` Eli Zaretskii
2021-04-02 17:07 ` Jean Louis
2021-04-03 4:49 ` Arthur Miller
2021-04-16 20:41 ` Emanuel Berg via Users list for the GNU Emacs text editor
2021-04-17 10:53 ` Jean Louis
2021-04-19 10:51 ` Eric S Fraga
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