Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.python > #98561

Re: Question about math.pi is mutable

From Ben Finney <ben+python@benfinney.id.au>
Newsgroups comp.lang.python
Subject Re: Question about math.pi is mutable
Date 2015-11-10 10:21 +1100
Message-ID <mailman.192.1447111281.16136.python-list@python.org> (permalink)
References (16 earlier) <CAPTjJmq--XE006MzxNe_3d_rmOP9GYxM_AxMF7Nh3d3RQbBx4g@mail.gmail.com> <mailman.160.1447031104.16136.python-list@python.org> <564081e7$0$1592$c3e8da3$5496439d@news.astraweb.com> <85fv0fgdnf.fsf@benfinney.id.au> <201511092007.tA9K7vbW000701@fido.openend.se>

Show all headers | View raw


Laura Creighton <lac@openend.se> writes:

> In a message of Tue, 10 Nov 2015 06:45:40 +1100, Ben Finney writes:
> >So the remaining space of code that is safe for the proposed
> >optimisation is trivially small. Why bother with such optimisations, if
> >the only code that can benefit is *already* small and simple?
>
> You have things backwards.
> The reason that you want to optimise this is that it is small, simple, 
> and slow_slow_slow_slow_slow.
>
> It is the things that are complicated and large that usually aren't
> worth optimising. You don't call them often enough for it to be worth
> it to optimise them.

I appreciate you making the the distinction explicit between a small and
simple *code unit* (e.g. an small, simple, often-called function),
versus a large and complex *code unit* (e.g. a large, complex,
infrequently-called class definition).

I'm pointing out an orthogonal issue: The only code to which the
proposed optimisation could apply is *module-level* (infrequently
called) code, which *has no complications* (i.e. not a code unit).

The simplicitly of the small section of code is not the issue; the
dynamism of the entire program is what negates the applicability of the
optimisation.

If the simple, predictable-by-the-compiler segment of code were actually
isolated in a simple unit, then yes, such optimisations might be
considered. But, as already discussed, the optimisation is not intended
to apply to such code units. So that is moot in this case.

Instead, we're talking about optimisations proposed *only* for
module-level code (i.e. not isolated); and what negates their
applicability is *any* dynamism (i.e. not simple), anywhere in the
program (i.e. not a code unit). The space of applicability for the
proposed optimisation shrinks to irrelevance, AFAICT.

-- 
 \        “If the arguments in favor of atheism upset you, explain why |
  `\        they’re wrong. If you can’t do that, that’s your problem.” |
_o__)                                     —Amanda Marcotte, 2015-02-13 |
Ben Finney

Back to comp.lang.python | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

Question about math.pi is mutable "wangq@travelsky.com" <wangq@travelsky.com> - 2015-11-06 10:33 +0800
  Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-06 12:30 +0000
    Re: Question about math.pi is mutable Lorenzo Sutton <lorenzofsutton@gmail.com> - 2015-11-06 17:12 +0100
      Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-06 19:30 +0000
        Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-07 06:40 +1100
          Re: Question about math.pi is mutable Christian Gollwitzer <auriocus@gmx.de> - 2015-11-06 20:59 +0100
          Re: Question about math.pi is mutable Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-11-06 23:19 +0100
            Re: Question about math.pi is mutable Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-11-07 00:48 +0100
            Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-07 13:00 +1100
        Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-07 14:43 +1100
          Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-07 11:23 +0000
            Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-07 22:35 +1100
              Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-07 11:57 +0000
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-07 23:15 +1100
                Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-07 13:00 +0000
                Re: Question about math.pi is mutable Laura Creighton <lac@openend.se> - 2015-11-07 15:09 +0100
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-07 16:23 +0200
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-07 16:28 +0200
                Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-07 15:01 +0000
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-07 19:46 +0200
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-08 14:07 +1100
                Re: Question about math.pi is mutable Random832 <random832@fastmail.com> - 2015-11-08 01:29 -0500
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-08 13:59 +1100
                Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-08 10:40 +0000
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-08 13:02 +0200
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 11:19 +0000
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-08 13:50 +0200
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 12:39 +0000
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-08 14:43 +0200
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 13:42 +0000
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-08 16:33 +0200
                Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-09 02:11 +1100
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-09 11:58 +1100
                Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-08 23:28 +1100
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-09 11:35 +1100
                Re: Question about math.pi is mutable Michael Torrie <torriem@gmail.com> - 2015-11-08 08:59 -0700
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 17:54 +0000
                Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-09 05:01 +1100
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 18:58 +0000
                Re: Question about math.pi is mutable Ian Kelly <ian.g.kelly@gmail.com> - 2015-11-08 12:51 -0700
                Re: Question about math.pi is mutable Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-11-08 18:13 -0500
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 23:54 +0000
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-09 11:00 +1100
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-09 00:11 +0000
                Re: Question about math.pi is mutable Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-11-09 08:18 -0500
                Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-09 11:04 +1100
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-09 11:26 +1100
                Re: Question about math.pi is mutable Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-11-09 21:29 +1300
                Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-09 11:36 +1100
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-09 11:50 +1100
                Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-09 11:56 +1100
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-09 12:04 +1100
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-09 22:22 +1100
                Re: Question about math.pi is mutable Random832 <random832@fastmail.com> - 2015-11-09 10:32 -0500
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-10 06:45 +1100
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-10 13:37 +1100
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-10 17:10 +1100
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-10 22:34 +1100
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-10 13:26 +0000
                Re: Question about math.pi is mutable Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-11-11 18:38 +1100
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-11 10:30 +0200
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-11 22:20 +1100
                Re: Question about math.pi is mutable Terry Reedy <tjreedy@udel.edu> - 2015-11-10 03:30 -0500
                Re: Question about math.pi is mutable Laura Creighton <lac@openend.se> - 2015-11-10 11:33 +0100
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-10 23:14 +1100
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-11 12:10 +1100
                Re: Question about math.pi is mutable Laura Creighton <lac@openend.se> - 2015-11-09 21:07 +0100
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-10 10:21 +1100
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-09 16:54 +0000
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-10 06:52 +1100
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-09 08:00 +1100
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 22:35 +0000
                Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-09 09:54 +1100
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-09 13:23 +1100
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-09 12:22 +0000
                Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-09 23:36 +1100
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-08 22:30 +1100
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 12:24 +0000
                Re: Question about math.pi is mutable Grant Edwards <invalid@invalid.invalid> - 2015-11-07 16:16 +0000
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-07 20:00 +0200
                Re: Question about math.pi is mutable Grant Edwards <invalid@invalid.invalid> - 2015-11-08 03:31 +0000
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-08 09:45 +0200
                Re: Question about math.pi is mutable Christian Gollwitzer <auriocus@gmx.de> - 2015-11-08 09:00 +0100
                Re: Question about math.pi is mutable Paul Rubin <no.email@nospam.invalid> - 2015-11-08 00:08 -0800
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-08 11:49 +0200
                Re: Question about math.pi is mutable Grant Edwards <invalid@invalid.invalid> - 2015-11-09 14:49 +0000
                Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-07 15:19 +0000
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-08 14:50 +1100
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-08 11:44 +0200
                Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-08 22:11 +1100
                Re: Question about math.pi is mutable Marko Rauhamaa <marko@pacujo.net> - 2015-11-08 13:25 +0200
                Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-08 11:06 +0000
        Re: Question about math.pi is mutable Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-09 15:49 +0100
        Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-10 10:29 +1100
        Re: Question about math.pi is mutable Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-10 11:03 +0100
        Re: Question about math.pi is mutable Michael Torrie <torriem@gmail.com> - 2015-11-13 20:11 -0700
        Re: Question about math.pi is mutable Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2015-11-14 16:02 +0100
    Re: Question about math.pi is mutable Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-11-06 23:26 +0100
      Re: Question about math.pi is mutable Terry Reedy <tjreedy@udel.edu> - 2015-11-06 20:49 -0500
      Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-07 13:06 +1100
      Re: Question about math.pi is mutable Bartc <bc@freeuk.com> - 2015-11-07 23:02 +0000
        Re: Question about math.pi is mutable Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-11-07 23:27 +0000
        Re: Question about math.pi is mutable Ben Finney <ben+python@benfinney.id.au> - 2015-11-08 10:32 +1100
        Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-08 10:52 +1100
          Re: Question about math.pi is mutable Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-11-12 21:40 +0100
            Re: Question about math.pi is mutable Steven D'Aprano <steve@pearwood.info> - 2015-11-13 09:04 +1100
              Re: Question about math.pi is mutable Denis McMahon <denismfmcmahon@gmail.com> - 2015-11-13 09:19 +0000
                Re: Question about math.pi is mutable Larry Hudson <orgnut@yahoo.com> - 2015-11-13 18:30 -0800
            Re: Question about math.pi is mutable BartC <bc@freeuk.com> - 2015-11-12 22:19 +0000
              Re: Question about math.pi is mutable Chris Angelico <rosuav@gmail.com> - 2015-11-13 09:52 +1100

csiph-web