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From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: [musl] casinh function accuracy problem
Date: Tue, 11 Feb 2020 21:00:23 -0500	[thread overview]
Message-ID: <20200212020023.GV1663@brightrain.aerifal.cx> (raw)
In-Reply-To: <alpine.LRH.2.02.2002121031560.9274@key0.esi.com.au>

On Wed, Feb 12, 2020 at 11:46:08AM +1100, Damian McGuckin wrote:
> On Tue, 11 Feb 2020, Rich Felker wrote:
> 
> >High-quality complex math functions are a long-term wishlist item for
> >musl but nobody has stepped up to do them and I don't really feel like
> >doing it, at least not over other improvements I could be working on.
> 
> As you say, they do work reasonably well even now.
> 
> With even complex arithmetic being "unspecified" in IEEE-754-2019,
> it is an interesting issue where "interesting" does not have the
> conventional English sense of being a positive thing.
> 
> >This might be an area well-served by sponsored enhancement if there's
> >a user who needs them improved with resources to pay someone to do it.
> 
> Depending on your definition of "improved", it is anything from a
> big task to a huge task.
> 
> And sadly, I have other things on my plate too.

My minimal criterion for large-scale improvements of src/complex would
be fixing any remaining cases where inf/nan behavior is badly wrong or
there's catastrophic error (>2^52 ulp, or even just >2^20 ulp or so).
Beyond that, I think "reducing ulp error" would be nice but hard to
quantify and make a goal without having an idea how bad it is now, not
to mention without having rigorous error bounds on the real math
library functions.

Rich

  reply	other threads:[~2020-02-12  2:00 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-11 15:51 mg1633068
2020-02-11 19:30 ` Szabolcs Nagy
2020-02-11 23:24   ` Rich Felker
2020-02-12  0:46     ` Damian McGuckin
2020-02-12  2:00       ` Rich Felker [this message]
2020-02-12  4:07         ` Damian McGuckin
2020-02-12  4:19           ` Rich Felker

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