Author mark.dickinson
Recipients AjithRamachandran, lemburg, mark.dickinson, rhettinger, serhiy.storchaka, stutzbach
Date 2021-06-09.09:02:57
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BTW, to forestall questions about adding cmath.cbrt: it's not obvious how to extend the real cube root function to a complex cube root, so it might make sense to wait for actual use-cases before doing so.

The issue is that the most natural way to define a complex cube root would use a branch cut along the negative real axis (the same branch cut that cmath.sqrt and cmath.log use). But then the principal branch would *not* be an extension of math.cbrt: it would return non-real values on the negative real axis. (The *real* cube roots of negative numbers would fall on the two non-principal branches.)

See for example https://math.stackexchange.com/questions/71775/extending-the-cube-root-function-to-mathbbc
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Date User Action Args
2021-06-09 09:02:58mark.dickinsonsetrecipients: + mark.dickinson, lemburg, rhettinger, stutzbach, serhiy.storchaka, AjithRamachandran
2021-06-09 09:02:57mark.dickinsonsetmessageid: <1623229377.99.0.97367824118.issue44357@roundup.psfhosted.org>
2021-06-09 09:02:57mark.dickinsonlinkissue44357 messages
2021-06-09 09:02:57mark.dickinsoncreate