Re: OT: This Swift thing

References	(12 earlier) <53990bad$0$29988$c3e8da3$5496439d@news.astraweb.com> <mailman.11028.1402548495.18130.python-list@python.org> <53996daa$0$11121$c3e8da3@news.astraweb.com> <4d836855-08a0-434d-b3ee-c1ff17057678@googlegroups.com> <5399ddaf$0$29988$c3e8da3$5496439d@news.astraweb.com>
Date	2014-06-13 03:18 +1000
Subject	Re: OT: This Swift thing
From	Chris Angelico <rosuav@gmail.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.11037.1402593488.18130.python-list@python.org> (permalink)

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On Fri, Jun 13, 2014 at 3:04 AM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> Chris made the argument that *the laws of physics* put limits on what we
> can attain, which is fair enough, but then made the poor example of speed
> limits on roads falling short of the speed of light. Yes, speed limits on
> roads fall considerably short of the speed of light, but not because of
> laws of physics. The speed limit in my street is 50 kilometres per hour,
> not because that limit is a law of physics, or because cars are incapable
> of exceeding 50kph, but because the government where I live has decided
> that 50kph is the maximum safe speed for a car to travel in my street,
> rounded to the nearest multiple of 10kph.
>
> In other words, Chris' example is a poor one to relate to the energy
> efficiency of computing.

The point isn't so much the legal or safe limit as that that's the
speed of most driving. That is to say: Around here, most cars will
travel at roughly 50 kph, which is a far cry from c. There are other
reasons than physics for choosing a speed.

> Take three numbers, speeds in this case, s1, s2 and c, with c a strict
> upper-bound. We can take:
>
> s1 < s2 < c
>
> without loss of generality. So in this case, we say that s2 is greater
> than s1:
>
> s2 > s1
>
> Adding the constant c to both sides does not change the inequality:
>
> c + s2 > c + s1

As long as we accept that this is purely in a mathematical sense.
Let's not get into the realm of actual speeds greater than c.

> Subtracting s1 + s2 from each side:
>
> c + s2 - (s1 + s2) > c + s1 - (s1 + s2)
> c - s1 > c - s2
>
> In other words, if 250mph is larger than 150mph (a fact, as you accept),
> then it is equally a fact that 250mph is closer to the speed of light
> than 150mph. You cannot possibly have one and not the other. So why do
> you believe that the first form is acceptable, but the second form is
> nonsense?

And at this point the calculation becomes safe again, and obvious
common sense. (Or alternatively, substitute Mach 1 for c; it's not a
hard limit, but there are good reasons for staying below it in
practical application - most airliners cruise a smidge below the speed
of sound for efficiency.)

> If I were arguing that there are no engineering limits prohibiting CPUs
> reaching Landauer's limit, then you could criticise me for that, but I'm
> not making that argument.
>
> I'm saying that, whatever the practical engineering limits turn out to
> be, we're unlikely to be close to them, and therefore there are very
> likely to be many and massive efficiency gains to be made in computing.

And this I totally agree with. The limits of physics are so incredibly
far from where we now are that we can utterly ignore them; the limits
we face are generally engineering (with the exception of stuff
designed for humans to use, eg minimum useful key size is defined by
fingers and not by what we can build).

ChrisA

Thread

OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-03 17:28 +0000
  Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 10:14 +0200
    Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-05 18:38 +1000
      Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 11:42 +0200
        Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-05 22:48 +1000
          Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 22:27 +0200
            Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-05 22:28 +0100
            Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 23:03 +0000
              Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 13:21 +0200
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-07 01:54 +0000
                Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-07 10:20 +0200
                Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-07 09:32 +0100
                Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-07 11:54 +0200
                Re: OT: This Swift thing Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-06-15 10:55 +0200
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 08:52 -0400
                Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-07 11:13 -0400
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 11:54 -0400
                Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-07 17:10 -0400
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-07 23:32 +0000
            Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-06 00:41 +0100
            Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-06 01:54 +0200
              Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-05 20:13 -0400
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-06 02:35 +0200
              Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-06 05:45 +0000
              Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 13:39 +0200
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-07 01:54 +0000
            Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-06 02:03 +0200
    Re: OT: This Swift thing wxjmfauth@gmail.com - 2014-06-05 02:09 -0700
    Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 16:10 +0200
      Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 22:07 +0200
        Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 06:18 +1000
          Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-05 23:12 +0200
            Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 23:02 +0000
        Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-05 22:23 +0100
          Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-06 00:53 +0300
            Re: OT: This Swift thing Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-06-05 23:13 +0100
              Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-06 02:52 +0000
            Re: OT: This Swift thing Johannes Bauer <dfnsonfsduifb@gmx.de> - 2014-06-15 11:33 +0200
              Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-15 16:10 +0300
        Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 07:36 +1000
          Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 13:20 +0200
            Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 22:23 +1000
            Re: OT: This Swift thing Christian Gollwitzer <auriocus@gmx.de> - 2014-06-07 09:30 +0200
        Re: OT: This Swift thing Terry Reedy <tjreedy@udel.edu> - 2014-06-05 18:18 -0400
          Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 13:11 +0200
            Re: OT: This Swift thing Terry Reedy <tjreedy@udel.edu> - 2014-06-06 13:06 -0400
            Re: OT: This Swift thing alex23 <wuwei23@gmail.com> - 2014-06-10 15:32 +1000
        Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 23:02 +0000
        Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-05 23:08 +0000
        Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 23:08 +0000
        Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 09:21 +1000
          Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-06 03:16 +0000
            Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 13:27 +1000
    Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-05 08:33 -0600
    Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-06 01:44 +1000
    Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-05 18:09 +0200
    Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-05 11:18 -0600
      Re: OT: This Swift thing Mark H Harris <harrismh777@gmail.com> - 2014-06-05 13:49 -0500
    Re: OT: This Swift thing Travis Griggs <travisgriggs@gmail.com> - 2014-06-05 23:28 -0700
      Re: OT: This Swift thing Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2014-06-06 10:25 +0200
    Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-06 20:41 -0600
      Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-07 04:57 +0000
        Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-07 11:23 -0400
          Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 11:51 -0400
            Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-07 19:18 +0300
              Re: OT: This Swift thing MRAB <python@mrabarnett.plus.com> - 2014-06-08 15:10 +0100
        Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-07 11:37 -0600
          Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 14:11 -0400
            Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-07 13:00 -0600
              Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 15:11 -0400
            Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-07 17:59 -0400
              Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-08 13:25 +1200
            Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-07 23:38 +0000
              Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-07 20:09 -0400
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-08 10:37 +1000
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-08 03:50 +0000
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-08 10:51 -0400
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-08 11:21 -0400
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-08 12:09 -0400
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-08 13:14 -0400
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-09 03:25 +1000
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-08 18:09 +0000
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-09 04:16 +1000
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-09 01:44 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-08 19:24 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-09 04:20 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-08 23:32 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-09 09:27 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-09 04:51 -0700
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-11 19:41 +1200
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-11 13:44 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-11 08:28 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-12 02:08 +0000
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-12 12:16 +1000
                Re: OT: This Swift thing Steven D'Aprano <steve@pearwood.info> - 2014-06-12 09:06 +0000
                Re: OT: This Swift thing alister <alister.nospam.ware@ntlworld.com> - 2014-06-12 09:34 +0000
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-12 23:32 +1200
                Re: OT: This Swift thing Anssi Saari <as@sci.fi> - 2014-06-16 13:57 +0300
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-17 10:12 +1200
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-17 08:34 +1000
                Re: OT: This Swift thing alister <alister.nospam.ware@ntlworld.com> - 2014-06-17 11:16 +0000
                Re: OT: This Swift thing Bob Martin <bob.martin@excite.com> - 2014-06-18 07:41 +0100
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-12 05:54 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-12 17:04 +0000
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-13 03:18 +1000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-12 18:59 -0700
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-13 03:26 +0000
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-12 14:43 -0400
                Re: OT: This Swift thing albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-06-27 23:21 +0000
                Re: OT: This Swift thing Joshua Landau <joshua@landau.ws> - 2014-06-15 02:51 +0100
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-15 03:33 +0000
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-09 10:11 -0400
                Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-09 17:27 +0300
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-11 18:56 +1200
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-09 09:14 -0400
                Re: OT: This Swift thing Michael Torrie <torriem@gmail.com> - 2014-06-09 07:56 -0600
                Re: OT: This Swift thing Marko Rauhamaa <marko@pacujo.net> - 2014-06-09 17:30 +0300
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-08 19:35 -0700
                Re: OT: This Swift thing Chris Angelico <rosuav@gmail.com> - 2014-06-09 12:23 +1000
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-11 19:50 +1200
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-11 12:34 +0000
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-11 08:48 -0400
                Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-11 20:17 -0400
                Re: OT: This Swift thing Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-06-12 01:25 +0000
                Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-12 14:11 +1200
                Re: OT: This Swift thing Gene Heskett <gheskett@wdtv.com> - 2014-06-11 23:06 -0400
                Re: OT: This Swift thing Roy Smith <roy@panix.com> - 2014-06-13 08:55 -0400
                Re: OT: This Swift thing Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-06-09 21:51 -0400
                Re: OT: This Swift thing Carlos Anselmo Dias <carlos@premium-sponsor.com> - 2014-06-08 18:56 +0100
                Re: OT: This Swift thing Sturla Molden <sturla.molden@gmail.com> - 2014-06-08 23:34 +0000
                Re: OT: This Swift thing Rustom Mody <rustompmody@gmail.com> - 2014-06-08 19:32 -0700
          Re: OT: This Swift thing Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-06-08 13:09 +1200

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