[New-bugs-announce] [issue4224] ** operating incorrectly for negative bases?

Martin Green report at bugs.python.org
Tue Oct 28 22:53:14 CET 2008

New submission from Martin Green <martin.speleo at gmail.com>:

I suspect that the following behavior is incorrect:

Python 2.5.2 (r252:60911, Feb 21 2008, 13:11:45) [MSC v.1310 32 bit
(Intel)] on win32
>>> -1**2
>>> -2**2
>>> -1**0.5

The same happens when the base is a float.
I have not checked out the functionality of other versions of python

The function pow (which claims to be equivalent to **) works as I would

>>> pow(-1, 2)
>>> pow(-2, 2)
>>> pow(-1, 0.5)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: negative number cannot be raised to a fractional power

I was not sure which components to select, please change them if I got
it wrong.

assignee: theller
components: Tests, ctypes
messages: 75304
nosy: martin.speleo, theller
severity: normal
status: open
title: ** operating incorrectly for negative bases?
type: behavior
versions: Python 2.5

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