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* Accuracy of Mathematical Functions in Single, Double, and Quadruple Precision
@ 2020-12-04 16:03 Paul Zimmermann
  2020-12-04 17:18 ` Joseph Myers
  0 siblings, 1 reply; 3+ messages in thread
From: Paul Zimmermann @ 2020-12-04 16:03 UTC (permalink / raw)
  To: libc-alpha

       Hi,

I have published a new version of my note, including results for double and
quadruple precision, and also for bivariate functions (atan2, hypot, pow):

https://homepages.loria.fr/PZimmermann/papers/#accuracy

In short, the GNU libc is the second best library in terms of accuracy,
behind the Intel Math Library.

Paul

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Accuracy of Mathematical Functions in Single, Double, and Quadruple Precision
  2020-12-04 16:03 Accuracy of Mathematical Functions in Single, Double, and Quadruple Precision Paul Zimmermann
@ 2020-12-04 17:18 ` Joseph Myers
  2020-12-07 10:34   ` Paul Zimmermann
  0 siblings, 1 reply; 3+ messages in thread
From: Joseph Myers @ 2020-12-04 17:18 UTC (permalink / raw)
  To: Paul Zimmermann; +Cc: libc-alpha

On Fri, 4 Dec 2020, Paul Zimmermann wrote:

>        Hi,
> 
> I have published a new version of my note, including results for double and
> quadruple precision, and also for bivariate functions (atan2, hypot, pow):
> 
> https://homepages.loria.fr/PZimmermann/papers/#accuracy

Thanks.  The errors above 9ulps that you found for tgamma and lgamma for 
binary128 would be good to mention in the bugs you opened for those 
functions for double, as they're evidence improvements are needed for 
those functions for binary128 as well.

> In short, the GNU libc is the second best library in terms of accuracy,
> behind the Intel Math Library.

I think the FreeBSD libm would be worth testing as well and may well be 
quite good - but may be harder to include as you'd need to run the tests 
on a FreeBSD system.

-- 
Joseph S. Myers
joseph@codesourcery.com

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Accuracy of Mathematical Functions in Single, Double, and Quadruple Precision
  2020-12-04 17:18 ` Joseph Myers
@ 2020-12-07 10:34   ` Paul Zimmermann
  0 siblings, 0 replies; 3+ messages in thread
From: Paul Zimmermann @ 2020-12-07 10:34 UTC (permalink / raw)
  To: Joseph Myers; +Cc: libc-alpha

       Dear Joseph,

> Thanks.  The errors above 9ulps that you found for tgamma and lgamma for 
> binary128 would be good to mention in the bugs you opened for those 
> functions for double, as they're evidence improvements are needed for 
> those functions for binary128 as well.

done. I found an error of 11.8884 ulps for lgamma, and 10.1539 ulps for tgamma.

Paul

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2020-12-04 16:03 Accuracy of Mathematical Functions in Single, Double, and Quadruple Precision Paul Zimmermann
2020-12-04 17:18 ` Joseph Myers
2020-12-07 10:34   ` Paul Zimmermann

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