JDK-8326530 : Widen allowable error bound of Math.tan
  • Type: Bug
  • Component: core-libs
  • Sub-Component: java.lang
  • Affected Version: 23
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2024-02-22
  • Updated: 2025-01-27
  • Resolved: 2024-02-23
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JDK 23
23 b12Fixed
Related Reports
CSR :  
JDK-8326537 - Widen allowable error bound of Math.tan
Relates :  
JDK-8316688 - Widen allowable error bound of Math.hypot
Relates :  
JDK-8316708 - Augment WorstCaseTests with more cases
Description
The method Math.tan has a 1 ulp error bound.

Recent work (https://members.loria.fr/PZimmermann/papers/accuracy.pdf) has found a case where the reference implementation of Math.tan has a 1.02 ulp error, which is (slightly) larger than the stated bound. The problematic input is 0x1.3f9605aaeb51bp+21.

The specification should be amended to accommodate the larger observed error bound.
Comments
A pull request was submitted for review. Branch: master URL: https://git.openjdk.org/jdk/pull/17973 Date: 2024-02-22 22:00:26 +0000
17-10-2024
Changeset: 63f6a563 Author: Joe Darcy <darcy@openjdk.org> Date: 2024-02-23 18:03:02 +0000 URL: https://git.openjdk.org/jdk/commit/63f6a563a3987d74ef673718d5209cc7c469751c
23-02-2024