[Python-ideas] complex number and fractional exponent (original) (raw)

Terry Reedy tjreedy at udel.edu
Sat Jan 26 20:09:44 CET 2013

On 1/26/2013 7:01 AM, Vito De Tullio wrote:

There is some ideas about extending the pow() / ** operator to return complex number when necessary?

As other have noted, it was. But the analogy with division is not exact. The new // operator was added for when one wants floor(a/b).

For sqrt, one also has a choice and always has since complexes were added.

import math, cmath math.sqrt(-1) Traceback (most recent call last): File "<pyshell#1>", line 1, in math.sqrt(-1) ValueError: math domain error cmath.sqrt(-1) 1j

For many purposes, such as computing standard deviation in statistics, one wants the exception, as negative variance indicates a calculation error.

-- Terry Jan Reedy

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