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* [ruby-core:103453] [Ruby master Bug#17804] Math.cbrt(0.0) returns NaN
@ 2021-04-15  1:17 ray.chason
  2021-04-15  1:34 ` [ruby-core:103456] " xtkoba+ruby
  2021-04-28 21:36 ` [ruby-core:103647] " merch-redmine
  0 siblings, 2 replies; 3+ messages in thread
From: ray.chason @ 2021-04-15  1:17 UTC (permalink / raw)
  To: ruby-core

Issue #17804 has been reported by chasonr (Ray chason).

----------------------------------------
Bug #17804: Math.cbrt(0.0) returns NaN
https://bugs.ruby-lang.org/issues/17804

* Author: chasonr (Ray chason)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.0.1p64 (2021-04-05 revision 0fb782ee38) [x86_64-linux]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
Math.cbrt(0.0) returns NaN. It should return 0.0.

From reading the implementation, I expect this bug to happen only if glibc is in use. The failing section reads:

#if defined __GLIBC__
    if (isfinite(r)) {
	r = (2.0 * r + (f / r / r)) / 3.0;
    }
#endif

and this produces a NaN when f and r are both 0.



-- 
https://bugs.ruby-lang.org/

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

* [ruby-core:103456] [Ruby master Bug#17804] Math.cbrt(0.0) returns NaN
  2021-04-15  1:17 [ruby-core:103453] [Ruby master Bug#17804] Math.cbrt(0.0) returns NaN ray.chason
@ 2021-04-15  1:34 ` xtkoba+ruby
  2021-04-28 21:36 ` [ruby-core:103647] " merch-redmine
  1 sibling, 0 replies; 3+ messages in thread
From: xtkoba+ruby @ 2021-04-15  1:34 UTC (permalink / raw)
  To: ruby-core

Issue #17804 has been updated by xtkoba (Tee KOBAYASHI).


FWIW, that code was introduced by commit commit:c995315153f7403636ec0d6119b7885668b32039.

----------------------------------------
Bug #17804: Math.cbrt(0.0) returns NaN
https://bugs.ruby-lang.org/issues/17804#change-91551

* Author: chasonr (Ray Chason)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.0.1p64 (2021-04-05 revision 0fb782ee38) [x86_64-linux]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
Math.cbrt(0.0) returns NaN. It should return 0.0.

From reading the implementation, I expect this bug to happen only if glibc is in use. The failing section reads:

#if defined __GLIBC__
    if (isfinite(r)) {
	r = (2.0 * r + (f / r / r)) / 3.0;
    }
#endif

and this produces a NaN when f and r are both 0.



-- 
https://bugs.ruby-lang.org/

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

* [ruby-core:103647] [Ruby master Bug#17804] Math.cbrt(0.0) returns NaN
  2021-04-15  1:17 [ruby-core:103453] [Ruby master Bug#17804] Math.cbrt(0.0) returns NaN ray.chason
  2021-04-15  1:34 ` [ruby-core:103456] " xtkoba+ruby
@ 2021-04-28 21:36 ` merch-redmine
  1 sibling, 0 replies; 3+ messages in thread
From: merch-redmine @ 2021-04-28 21:36 UTC (permalink / raw)
  To: ruby-core

Issue #17804 has been updated by jeremyevans0 (Jeremy Evans).


I've submitted a pull request to fix this: https://github.com/ruby/ruby/pull/4425 

----------------------------------------
Bug #17804: Math.cbrt(0.0) returns NaN
https://bugs.ruby-lang.org/issues/17804#change-91743

* Author: chasonr (Ray Chason)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.0.1p64 (2021-04-05 revision 0fb782ee38) [x86_64-linux]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
Math.cbrt(0.0) returns NaN. It should return 0.0.

From reading the implementation, I expect this bug to happen only if glibc is in use. The failing section reads:

#if defined __GLIBC__
    if (isfinite(r)) {
	r = (2.0 * r + (f / r / r)) / 3.0;
    }
#endif

and this produces a NaN when f and r are both 0.



-- 
https://bugs.ruby-lang.org/

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

end of thread, other threads:[~2021-04-28 21:36 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-04-15  1:17 [ruby-core:103453] [Ruby master Bug#17804] Math.cbrt(0.0) returns NaN ray.chason
2021-04-15  1:34 ` [ruby-core:103456] " xtkoba+ruby
2021-04-28 21:36 ` [ruby-core:103647] " merch-redmine

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