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Re: (-1)**1000

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From Ned Batchelder <ned@nedbatchelder.com>
Subject Re: (-1)**1000
Date Sun, 26 Oct 2014 16:45:12 -0400
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On 10/26/14 4:07 PM, Tony the Tiger wrote:
> On Wed, 22 Oct 2014 10:27:34 +0200, ast wrote:
>
>> If i am writing (-1)**1000 on a python program, will the interpreter do
>> (-1)*(-1)*...*(-1) or something clever ?
>
> Even vs. odd. It ought to know. I would assume from a set of defined
> rules how math works.

There is such a thing as an optimization that isn't worthwhile to 
perform, simply because it's expected to provide so little benefit.  The 
language implementors have to trade off the cost of adding the 
optimization to the implementation, against the possible benefit people 
would get from it.

Benefit in this case would have to include a guess as to how often real 
programs would hit the optimization case.

-- 
Ned Batchelder, http://nedbatchelder.com

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Thread

(-1)**1000 "ast" <nomail@invalid.com> - 2014-10-22 10:27 +0200
  Re: (-1)**1000 Chris Angelico <rosuav@gmail.com> - 2014-10-22 19:54 +1100
    Re: (-1)**1000 "ast" <nomail@invalid.com> - 2014-10-22 11:27 +0200
      Re: (-1)**1000 Peter Otten <__peter__@web.de> - 2014-10-22 12:29 +0200
      Re: (-1)**1000 Michiel Overtoom <motoom@xs4all.nl> - 2014-10-22 12:38 +0200
      Re: (-1)**1000 Tim Chase <python.list@tim.thechases.com> - 2014-10-22 05:43 -0500
      Re: (-1)**1000 Peter Otten <__peter__@web.de> - 2014-10-22 13:02 +0200
      Re: (-1)**1000 Ian Kelly <ian.g.kelly@gmail.com> - 2014-10-22 08:23 -0600
      Re: (-1)**1000 Ian Kelly <ian.g.kelly@gmail.com> - 2014-10-22 08:29 -0600
      Re: (-1)**1000 Ned Batchelder <ned@nedbatchelder.com> - 2014-10-22 11:01 -0400
        Re: (-1)**1000 albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-11-04 00:46 +0000
    Re: (-1)**1000 wxjmfauth@gmail.com - 2014-10-22 04:35 -0700
  Re: (-1)**1000 Peter Otten <__peter__@web.de> - 2014-10-22 11:13 +0200
  Re: (-1)**1000 Terry Reedy <tjreedy@udel.edu> - 2014-10-22 13:15 -0400
  Re: (-1)**1000 Dave Angel <davea@davea.name> - 2014-10-24 13:57 -0400
  Re: (-1)**1000 Tony the Tiger <tony@tiger.invalid> - 2014-10-26 20:07 +0000
    Re: (-1)**1000 Ned Batchelder <ned@nedbatchelder.com> - 2014-10-26 16:45 -0400
    Re: (-1)**1000 Stefan Behnel <stefan_ml@behnel.de> - 2014-10-29 20:31 +0100

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