From: Joseph Myers <joseph@codesourcery.com>
To: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: Michael Hudson-Doyle <michael.hudson@canonical.com>,
GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH] Ensure calculations happen with desired rounding mode in y1lf128
Date: Wed, 17 Aug 2022 16:52:36 +0000 [thread overview]
Message-ID: <alpine.DEB.2.22.394.2208171647290.417173@digraph.polyomino.org.uk> (raw)
In-Reply-To: <AM5PR0801MB1668EC9F8A41F189B0C0B191836A9@AM5PR0801MB1668.eurprd08.prod.outlook.com>
On Wed, 17 Aug 2022, Wilco Dijkstra via Libc-alpha wrote:
> When you design a polynomial to be very accurate, it actually works in
> all rounding modes without extra effort. For this function it seems like
In the Bessel function case, accurate results near zeros in the
intermediate range (the range where multiple terms of a series are needed
before applying range reduction, see Harrison's paper
<https://www.cl.cam.ac.uk/~jrh13/papers/bessel.pdf>) may require extra
internal precision when computing the phase. And some precision extension
techniques only work in round-to-nearest (we only have that Bessel
function approach implemented in glibc for float, where using double
internally avoids such rounding mode problems for precision extension).
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2022-08-17 16:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-12 12:28 Wilco Dijkstra
2022-08-15 20:59 ` Joseph Myers
2022-08-17 4:23 ` Michael Hudson-Doyle
2022-08-17 11:53 ` Wilco Dijkstra
2022-08-17 16:52 ` Joseph Myers [this message]
2022-08-22 12:28 ` Paul Zimmermann
-- strict thread matches above, loose matches on Subject: below --
2022-08-12 0:05 Michael Hudson-Doyle
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