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Accuracy of Mathematical Functions in Single Precision for glibc 2.31
- From: paul zimmermann <Paul dot Zimmermann at inria dot fr>
- To: libc-alpha at sourceware dot org
- Date: Mon, 03 Feb 2020 07:33:40 +0100
- Subject: Accuracy of Mathematical Functions in Single Precision for glibc 2.31
Hi,
I have checked by exhaustive search the accuracy of single precision
math functions on x86_64 (for rounding to nearest) in the just released
2.31 version:
https://homepages.loria.fr/PZimmermann/glibc/glibc231.pdf
Results are quite interesting, in particular:
- exp10 is close from being correctly rounded (only one exception)
- j0, j1, y0, y1 are quite bad (this was already known, but the "Known
Maximum Errors in Math Functions" in the reference manual do not reflect it)
- some functions have only very few cases with error >= 2 ulps
Paul Zimmermann