On Fri, 22 Sep 2023 05:36:02 GMT, Joe Darcy <da...@openjdk.org> wrote:
> A new paper > > "Accuracy of Mathematical Functions in Single, Double, Double Extended, and > Quadruple Precision" > by Brian Gladman, Vincenzo Innocente and Paul Zimmermann > https://members.loria.fr/PZimmermann/papers/accuracy.pdf > > details the inputs with generate the worst-case observed errors in different > math library implementations. The FDLIBM-related worst cases should be added > to the test suite. test/jdk/java/lang/Math/WorstCaseTests.java line 56: > 54: * sinh and cosh. > 55: * > 56: * Additional worst-case observed error inputs for the FDLIBM-dervied Suggestion: * Additional worst-case observed error inputs for the FDLIBM-derived test/jdk/java/lang/Math/WorstCaseTests.java line 325: > 323: > 324: // Worst-case observed error > 325: {0x1.3f9605aaeb51bp+21, -0x1.9678ee5d64935p-1}, The given expected value seems to contradict the introductory comment. The exact value y meets `-0x1.9678ee5d64935p-1` < y < `-0x1.9678ee5d64934p-1`, and is closer to `-0x1.9678ee5d64935p-1`. Thus, the rounded value of y is `-0x1.9678ee5d64935p-1`, but its truncated value is `-0x1.9678ee5d64934p-1`. This should be the expected value, but then the test fails. I don't think that the test logic can support errors > 1 ulp, as is the case here. Perhaps, rather than a single expected value, there should be explicit lower and upper bounds. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/15879#discussion_r1334533881 PR Review Comment: https://git.openjdk.org/jdk/pull/15879#discussion_r1334533360
