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From: Eli Zaretskii <eliz@gnu.org>
To: Max Nikulin <manikulin@gmail.com>
Cc: emacs-devel@gnu.org
Subject: Re: hypotenuse
Date: Sun, 21 Jul 2024 19:12:13 +0300	[thread overview]
Message-ID: <86frs2bu76.fsf@gnu.org> (raw)
In-Reply-To: <v7jb0d$nld$1@ciao.gmane.io> (message from Max Nikulin on Sun, 21 Jul 2024 22:54:53 +0700)

> From: Max Nikulin <manikulin@gmail.com>
> Date: Sun, 21 Jul 2024 22:54:53 +0700
> 
> On 21/07/2024 22:12, Christopher Dimech wrote:
> >>>> (defun hypotenuse (c1 c2)
> >>>>    (sqrt (+ (* c1 c1) (* c2 c2))) )
> > 
> > I have a solution to the problem in fortran, but not in elisp.  I could
> > include it.  Its implementation required serious concentration.
> 
> Underflow/overflow issues may be solved with a few lines of code and it 
> does matter if it is fortran, elisp, or another language (besides 
> pathological ones). The problem is to avoid error above 1 ULP.

Right, overflow and underflow are just the tip of a very large
iceberg.

> In 2021 hypot implementation in glibc was replaced by a more precise one:
> https://sourceware.org/git/?p=glibc.git;a=commit;h=6c848d70383e1dbe932ef41723ac0abfdeec7ca8

Which is exactly why I said we should use the existing implementation
in the standard library.



  reply	other threads:[~2024-07-21 16:12 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-12 16:47 Add elisa to GNU ELPA Sergey Kostyaev
2024-07-16 12:54 ` Philip Kaludercic
2024-07-16 13:57   ` Sergey Kostyaev
2024-07-16 16:04     ` Philip Kaludercic
2024-07-16 16:35       ` Sergey Kostyaev
2024-07-17 13:21         ` Andrew Hyatt
2024-07-16 16:41       ` Sergey Kostyaev
2024-07-16 17:02         ` Philip Kaludercic
2024-07-16 17:47           ` Adding a generic mathematical library Philip Kaludercic
2024-07-16 22:06             ` Emanuel Berg
2024-07-17  2:54               ` Christopher Dimech
2024-07-17  5:58                 ` Emanuel Berg
2024-07-19 16:16               ` Richard Stallman
2024-07-19 17:38                 ` Christopher Dimech
2024-07-21  5:20                   ` Emanuel Berg
2024-07-20 12:45                 ` Max Nikulin
2024-07-20 13:53                   ` Christopher Dimech
2024-07-21  5:19                 ` Emanuel Berg
2024-07-21  6:15                   ` Emanuel Berg
2024-07-21  7:40                     ` Emanuel Berg
2024-07-21  8:45                       ` Emanuel Berg
2024-07-21  8:29                     ` Emanuel Berg
2024-07-21  7:27                   ` Christopher Dimech
2024-07-21  8:03                     ` Emanuel Berg
2024-07-21  9:14                       ` Christopher Dimech
2024-07-21  9:48                         ` Emanuel Berg
2024-07-21 11:20                           ` Emanuel Berg
2024-07-21 11:53                             ` Christopher Dimech
2024-07-21 12:10                               ` Emanuel Berg
2024-07-21 12:27                                 ` Emanuel Berg
2024-07-21 12:46                                   ` Emanuel Berg
2024-07-21 13:03                                   ` Christopher Dimech
2024-07-21 13:17                                     ` Emanuel Berg
2024-07-21 14:33                                       ` Eli Zaretskii
2024-07-21 14:41                                         ` Christopher Dimech
2024-07-21 14:49                                           ` Eli Zaretskii
2024-07-21 14:58                                             ` Christopher Dimech
2024-07-21 15:02                                               ` Eli Zaretskii
2024-07-21 15:18                                                 ` Christopher Dimech
2024-07-21 13:18                                     ` Christopher Dimech
2024-07-21 13:26                                       ` Emanuel Berg
2024-07-21 14:35                                         ` Christopher Dimech
2024-07-21 19:28                                           ` Emanuel Berg
2024-07-21 19:33                                           ` Emanuel Berg
2024-07-21 19:51                                           ` Emanuel Berg
2024-07-21 20:01                                           ` Emanuel Berg
2024-07-21 20:17                                           ` Emanuel Berg
2024-07-21 12:41                                 ` Christopher Dimech
2024-07-21 13:13                                   ` Emanuel Berg
2024-07-21 13:41                                   ` Emanuel Berg
2024-07-21 12:20                               ` Emanuel Berg
2024-07-21 12:04                             ` Emanuel Berg
2024-07-21 14:30                 ` hypotenuse (was: Re: Adding a generic mathematical library) Emanuel Berg
2024-07-21 14:44                   ` Eli Zaretskii
2024-07-21 15:00                     ` Eli Zaretskii
2024-07-21 15:12                       ` Christopher Dimech
2024-07-21 15:42                         ` Eli Zaretskii
2024-07-21 16:13                           ` Christopher Dimech
2024-07-21 15:54                         ` hypotenuse Max Nikulin
2024-07-21 16:12                           ` Eli Zaretskii [this message]
2024-07-21 16:17                             ` hypotenuse Christopher Dimech
2024-07-21 19:01                     ` hypotenuse (was: Re: Adding a generic mathematical library) Emanuel Berg
2024-07-21 19:13                     ` Emanuel Berg
2024-07-21 17:38                   ` tomas
2024-07-17  7:09             ` Adding a generic mathematical library Michael Heerdegen via Emacs development discussions.
2024-07-17  7:54               ` Philip Kaludercic
2024-07-17  7:56               ` Michael Heerdegen via Emacs development discussions.
2024-07-18  6:07                 ` Emanuel Berg
2024-07-18  6:45                   ` Christopher Dimech
2024-07-18  7:12                     ` Emanuel Berg
2024-07-18  7:49                       ` Christopher Dimech
2024-07-21  4:56                         ` Emanuel Berg
2024-07-18  7:29                   ` Eli Zaretskii
2024-07-18  7:57                     ` Emanuel Berg
2024-07-18  9:03                       ` Eli Zaretskii
2024-07-21  4:52                         ` Emanuel Berg
2024-07-18  8:15                     ` Emanuel Berg
2024-07-18  9:04                       ` Eli Zaretskii
2024-07-18  9:13                       ` Christopher Dimech
2024-07-21  4:59                         ` Emanuel Berg
2024-07-19 13:22                       ` Emanuel Berg
2024-07-19 16:12                         ` Christopher Dimech
2024-07-19 16:15                           ` Stefan Kangas
2024-07-19 16:29                             ` Christopher Dimech
2024-07-19 16:16               ` Richard Stallman
2024-07-19 18:00                 ` Christopher Dimech
2024-07-17 21:26   ` Add elisa to GNU ELPA Sergey Kostyaev
2024-07-17 22:12     ` Philip Kaludercic
2024-07-18  3:45       ` Sergey Kostyaev
2024-07-18 11:06       ` Sergey Kostyaev

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