Towards the post-ultimate libm
Towards the post-ultimate libm
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迈向后终极自由主义
DOI：
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发表时间：
2005
期刊：
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通讯作者：
Nicolas Gast
中科院分区：
文献类型：
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作者：
F. D. Dinechin;A. Ershov;Nicolas Gast
本文介绍了自Ziv在IBM开发的libultim数学库出版以来，关于正确四舍五入初等函数主题的进展。这个库表明，正确舍入的平均性能和内存开销可以忽略不计。然而，最坏情况的开销仍然是1000倍甚至更多。结果表明，使用当前的处理器技术，这种最坏情况开销可以保持在当前最佳libms的2到10倍之内。这种低开销对实现和证明正确舍入函数的技术有非常积极的影响，这也是我们所研究的。这些结果消除了推广（至少一些）正确舍入双精度初等函数的最后技术障碍。
This article presents advances on the subject of correctly rounded elementary functions since the publication of the libultim mathematical library developed by Ziv at IBM. This library showed that the average performance and memory overhead of correct rounding could be made negligible. However, the worst-case overhead was still a factor 1000 or more. It is shown that, with current processor technology, this worst-case overhead can be kept within a factor of 2 to 10 of current best libms. This low overhead has very positive consequences on the techniques for implementing and proving correctly rounded functions, which are also studied. These results lift the last technical obstacles to a generalisation of (at least some) correctly rounded double precision elementary functions.