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From: Paul Zimmermann <Paul.Zimmermann@inria.fr>
To: DJ Delorie <dj@redhat.com>
Cc: alx@kernel.org, libc-alpha@sourceware.org
Subject: Re: [PATCH v2 3/3] manual: Cube roots are rarely representable
Date: Sat, 30 Mar 2024 08:07:32 +0100	[thread overview]
Message-ID: <p9u0sf08i4ej.fsf@coriandre.loria.fr> (raw)
In-Reply-To: <xnwmpk5zsv.fsf@greed.delorie.com> (message from DJ Delorie on Fri, 29 Mar 2024 20:27:44 -0400)

> From: DJ Delorie <dj@redhat.com>
> Cc: libc-alpha@sourceware.org
> Date: Fri, 29 Mar 2024 20:27:44 -0400
> 
> Alejandro Colomar <alx@kernel.org> writes:
> 
> > -These functions return the cube root of @var{x}.  They cannot
> > -fail; every representable real value has a representable real cube root.
> 
> > +These functions return the cube root of @var{x}.  They cannot
> > +fail; every representable real value has a real cube root,
> > +and rounding it to a representable value
> > +never causes overflow nor underflow.
> 
> Wording is OK but the $subject says the exact opposite...

It is fine to me. The subject says that the cube root of a floating-point
number is rarely a floating-point number, which is true: for a p-bit format,
only about 2^(p/3) numbers have an exact cube root.

Paul

  reply	other threads:[~2024-03-30  7:07 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CANv4PNkVv_0eLgiSP3L_KfC-eZJaVLZ5AP1AGfD0GNrR5M4Hrg@mail.gmail.com>
     [not found] ` <ZeEnJB96mMC5bfBz@debian>
     [not found]   ` <CANv4PNmMpiwfv5acr7U6VEVe7PE_AMTzkkpNoNN9jrtVzk_93Q@mail.gmail.com>
2024-03-02 21:54     ` Man page issues: logb, significand, cbrt, log2, log10, exp10 Alejandro Colomar
2024-03-03  2:02       ` Morten Welinder
2024-03-03  2:21         ` Alejandro Colomar
2024-03-03 11:46           ` Vincent Lefevre
2024-03-03 12:21             ` Alejandro Colomar
2024-03-03 22:26               ` Morten Welinder
2024-03-04 12:17         ` Adhemerval Zanella Netto
2024-03-05 16:12 ` [PATCH v2 0/3] manual/math.texi: logb(3) and cbrt(3) fixes Alejandro Colomar
2024-03-05 16:12   ` [PATCH v2 1/3] manual: logb(x) is floor(log2(fabs(x))) Alejandro Colomar
2024-03-29 22:08     ` DJ Delorie
2024-03-29 23:00       ` Alejandro Colomar
2024-03-05 16:12   ` [PATCH v2 2/3] manual: floor(log2(fabs(x))) has rounding errors Alejandro Colomar
2024-03-30  0:24     ` DJ Delorie
2024-03-30  9:27       ` Alejandro Colomar
2024-03-30  9:30         ` Alejandro Colomar
2024-03-30  9:47       ` Andreas Schwab
2024-03-05 16:12   ` [PATCH v2 3/3] manual: Cube roots are rarely representable Alejandro Colomar
2024-03-30  0:27     ` DJ Delorie
2024-03-30  7:07       ` Paul Zimmermann [this message]
2024-03-30 16:51         ` DJ Delorie
2024-03-30 18:42           ` Alejandro Colomar
2024-03-30 18:50             ` DJ Delorie
2024-03-30 19:07               ` Alejandro Colomar
2024-03-31 20:38   ` [PATCH v3 0/4] manual: arith.texi and math.texi fixes Alejandro Colomar
2024-03-31 20:38     ` [PATCH v3 1/4] manual: logb(x) is floor(log2(fabs(x))) Alejandro Colomar
2024-03-31 20:38     ` [PATCH v3 2/4] manual: floor(log2(fabs(x))) has rounding errors Alejandro Colomar
2024-03-31 20:38     ` [PATCH v3 3/4] manual: Clarify return value of cbrt(3) Alejandro Colomar
2024-04-01 18:57       ` DJ Delorie
2024-03-31 20:38     ` [PATCH v3 4/4] manual: significand() uses FLT_RADIX, not 2 Alejandro Colomar
2024-04-01 19:09       ` DJ Delorie

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