[issue23523] cmath.atanh has wrong output

Mark Dickinson added the comment: > Both are correct Well, strictly speaking only the output with positive imaginary part is correct here: the recommendations of C99 Annex G (which Python's cmath module follows) use the sign of the zero imaginary part to determine which 'side' of the branch cu

[issue23523] cmath.atanh has wrong output

Benjamin Peterson added the comment: Both are correct, since atanh requires a branch cut. -- nosy: +benjamin.peterson resolution: -> not a bug status: open -> closed ___ Python tracker

[issue23523] cmath.atanh has wrong output

Changes by Ezio Melotti : -- nosy: +ezio.melotti, mark.dickinson, rhettinger, stutzbach ___ Python tracker ___ ___ Python-bugs-list ma

[issue23523] cmath.atanh has wrong output

New submission from 夏熙临: When I was using cmath.atanh, I found that this function generates wrong output. For example: >>> import cmath >>> cmath.atanh(-1.89) (-0.5888951591901462+1.5707963267948966j) However, the correct output should be: (-0.5888951591901462-1.5707963267948966j) Clearly, th