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From: Giuliano Augusto Faulin Belinassi <giuliano.belinassi@usp.br>
To: Jeff Law <law@redhat.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,
	Paul Koning <paulkoning@comcast.net>
Subject: Re: [PATCH] Add sinh(tanh(x)) and cosh(tanh(x)) rules
Date: Wed, 17 Oct 2018 21:43:00 -0000	[thread overview]
Message-ID: <CAEFO=4DWEZr1j0xnJ_YWH38TNUT23hR9EccdMdZsr+z7g1MJqw@mail.gmail.com> (raw)
In-Reply-To: <6315400f-4ee5-2402-2808-7c6cb04b71d6@redhat.com>

> Hmm, do we have problems as we get close to -1 or 1 where the outputs of
> the two forms might diverge?

Well, I did some minor testing with that with input x around nextafter(1, -1);
There are a minor imprecision when comparing directly with
sinh(atanh(x)) and cosh(atanh(x)).
  * On 32-bits floats, for such x the error is about 10^-4
  * On 64-bits floats, for such x the error is about 10^-7
  * On 80-bits floats, for such x the error is about 10^-9

here are the code that I used for the test: https://pastebin.com/JzYZyigQ

I can create a testcase based on this if needed :-)

  reply	other threads:[~2018-10-17 21:26 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-07 20:00 Giuliano Augusto Faulin Belinassi
2018-08-07 20:29 ` Paul Koning
2018-08-07 20:42   ` Giuliano Augusto Faulin Belinassi
2018-08-08 13:59     ` Paul Koning
2018-08-08 18:57       ` Giuliano Augusto Faulin Belinassi
2018-08-08 19:55         ` Paul Koning
2018-10-12  4:55 ` Jeff Law
2018-10-12 14:55   ` Giuliano Augusto Faulin Belinassi
2018-10-16 21:16     ` Jeff Law
2018-10-17 21:43       ` Giuliano Augusto Faulin Belinassi [this message]
2018-10-17 22:45         ` Jeff Law
2018-10-18  5:38           ` Giuliano Augusto Faulin Belinassi
2018-10-18 17:10             ` Jeff Law
2018-10-18 22:46               ` Giuliano Belinassi
2018-10-18 23:22 Wilco Dijkstra
2018-10-19 13:39 ` Giuliano Augusto Faulin Belinassi
2018-10-19 13:46   ` Wilco Dijkstra
2018-10-19 14:49     ` Jakub Jelinek
2018-10-19 15:35       ` Wilco Dijkstra
2018-10-19 14:03   ` Segher Boessenkool
2018-10-19 15:10     ` Giuliano Augusto Faulin Belinassi
2018-10-19 17:28       ` Wilco Dijkstra
2018-10-20 19:06         ` Giuliano Augusto Faulin Belinassi
2018-10-22 20:58           ` Jeff Law
2018-10-23  9:52             ` Richard Biener
2018-10-23 11:31               ` Wilco Dijkstra
2018-10-23 11:35                 ` Jakub Jelinek
2018-10-23 12:02                   ` Wilco Dijkstra
2018-11-07 22:21               ` Jeff Law
2018-11-07 22:34                 ` Wilco Dijkstra
2018-11-08  1:44                   ` Segher Boessenkool
2018-11-08 13:33                     ` Wilco Dijkstra
2018-11-09 20:04                       ` Jeff Law
2018-11-09 22:04                         ` Giuliano Augusto Faulin Belinassi
2018-11-10  5:36                         ` Segher Boessenkool
2018-11-12 14:17                           ` Richard Biener
2018-12-02 14:37                       ` Segher Boessenkool

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