From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Paul Zimmermann <Paul.Zimmermann@inria.fr>, libc-alpha@sourceware.org
Subject: Re: [PATCH] Fix the inaccuracy of j0f/j1f/y0f/y1f [BZ #14469, #14470, #14471, #14472]
Date: Wed, 31 Mar 2021 15:37:55 -0300 [thread overview]
Message-ID: <fbeeb752-8404-4f77-c617-a08f20b46830@linaro.org> (raw)
In-Reply-To: <20210331061221.2215282-1-Paul.Zimmermann@inria.fr>
On 31/03/2021 03:12, Paul Zimmermann wrote:
> For j0f/j1f/y0f/y1f, the largest error for all binary32
> inputs is reduced to at most 9 ulps for all rounding modes.
>
> The new code is enabled only when there is a cancellation at the very end of
> the j0f/j1f/y0f/y1f computation, or for very large inputs, thus should not
> give any visible slowdown on average. Two different algorithms are used:
>
> * around the first 64 zeros of j0/j1/y0/y1, approximation polynomials of
> degree 3 are used, computed using the Sollya tool (https://www.sollya.org/)
>
> * for large inputs, an asymptotic formula from [1] is used
>
> [1] Fast and Accurate Bessel Function Computation,
> John Harrison, Proceedings of Arith 19, 2009.
>
> Inputs yielding the new largest errors are added to auto-libm-test-in,
> and ulps are regenerated for various targets (thanks Adhemerval Zanella).
>
> Tested on x86_64 with --disable-multi-arch and on powerpc64le-linux-gnu.
> ---
> math/auto-libm-test-in | 20 +-
> math/auto-libm-test-out-j0 | 50 +++
> math/auto-libm-test-out-j1 | 50 +++
> math/auto-libm-test-out-y0 | 50 +++
> math/auto-libm-test-out-y1 | 75 +++++
> sysdeps/aarch64/libm-test-ulps | 70 ++--
> sysdeps/ieee754/flt-32/e_j0f.c | 515 ++++++++++++++++++++++++++---
> sysdeps/ieee754/flt-32/e_j1f.c | 512 ++++++++++++++++++++++++++--
> sysdeps/powerpc/fpu/libm-test-ulps | 62 ++--
> sysdeps/s390/fpu/libm-test-ulps | 68 ++--
> sysdeps/sparc/fpu/libm-test-ulps | 68 ++--
> sysdeps/x86_64/fpu/libm-test-ulps | 76 ++---
> 12 files changed, 1371 insertions(+), 245 deletions(-)
Paul,
This version still misses the reduce_aux.h file.
next prev parent reply other threads:[~2021-03-31 18:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 6:12 Paul Zimmermann
2021-03-31 18:37 ` Adhemerval Zanella [this message]
2021-03-31 19:27 ` Paul Zimmermann
2021-03-31 19:28 ` Adhemerval Zanella
2021-03-31 19:31 ` Adhemerval Zanella
2021-04-01 6:15 ` Paul Zimmermann
-- strict thread matches above, loose matches on Subject: below --
2021-03-30 17:18 Paul Zimmermann
2021-03-30 18:18 ` Adhemerval Zanella
2021-03-30 18:41 ` Adhemerval Zanella
2021-03-31 5:57 ` Paul Zimmermann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=fbeeb752-8404-4f77-c617-a08f20b46830@linaro.org \
--to=adhemerval.zanella@linaro.org \
--cc=Paul.Zimmermann@inria.fr \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).