Re: Best search algorithm to find condition within a range

References	(7 earlier) <87fv89zd0m.fsf@elektro.pacujo.net> <87y4m1795n.fsf@dpt-info.u-strasbg.fr> <mailman.165.1428585562.12925.python-list@python.org> <874mopzarw.fsf@elektro.pacujo.net> <552696be$0$13012$c3e8da3$5496439d@news.astraweb.com>
Date	2015-04-10 01:34 +1000
Subject	Re: Best search algorithm to find condition within a range
From	Chris Angelico <rosuav@gmail.com>
Newsgroups	comp.lang.python
Message-ID	<mailman.169.1428593659.12925.python-list@python.org> (permalink)

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On Fri, Apr 10, 2015 at 1:11 AM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Thu, 9 Apr 2015 11:33 pm, Marko Rauhamaa wrote:
>
>> In this day and age, heavily optimized compilers (including gcc)
>> actively exploit undefined behavior in code generation.
>
> Optimization and undefined behaviour reminds me of a story my wife told me,
> of a time she was crossing the US with some roadies. As they were driving
> across the desert highway, one of the roadies noticed that they were
> driving in the wrong direction for their next gig.
>
> "Who cares?" said the driver, "we're making fantastic time!"

It's not really like that. Imagine you're loading up the stuff on the
back of your truck. Do you have to research the narrowest tunnel
you'll ever have to go through? Nah. You just make sure it's no wider
than the legal limit, because any tunnel that's narrower than that
isn't your problem. If you ever _do_ meet an overly-narrow tunnel,
you'll run into problems, because you assumed that such a thing wasn't
possible.

The C compiler is generally going to assume a whole slew of principles
that aren't technically guaranteed. For instance, it'll probably
assume that CPU registers will accurately retain what they were set
to, and likewise memory (unless it's marked 'volatile'). Put your code
out in space, and that might no longer be true, but you can't expect
the compiler to cope with that. As far as it's concerned, it's
impossible for a CPU register to arbitrarily change without notice.
It's equally impossible for the addition of two positive signed
integers to result in a negative integer.

ChrisA

Thread

Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 02:44 -0700
  Re: Best search algorithm to find condition within a range Dave Angel <davea@davea.name> - 2015-04-07 09:29 -0400
    Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 07:10 -0700
      Re: Best search algorithm to find condition within a range Dave Angel <davea@davea.name> - 2015-04-07 10:26 -0400
      Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-08 00:34 +1000
    Re: Best search algorithm to find condition within a range Denis McMahon <denismfmcmahon@gmail.com> - 2015-04-07 14:29 +0000
      Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 07:36 -0700
        Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-08 00:49 +1000
          Re: Best search algorithm to find condition within a range Grant Edwards <invalid@invalid.invalid> - 2015-04-07 15:05 +0000
            Re: Best search algorithm to find condition within a range Dave Angel <davea@davea.name> - 2015-04-07 11:23 -0400
            Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-08 01:37 +1000
            Re: Best search algorithm to find condition within a range MRAB <python@mrabarnett.plus.com> - 2015-04-07 17:02 +0100
        Re: Best search algorithm to find condition within a range MRAB <python@mrabarnett.plus.com> - 2015-04-07 16:00 +0100
          Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 08:43 -0700
            Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-08 08:51 +1000
              Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-08 11:46 +1000
        Re: Best search algorithm to find condition within a range Dave Angel <davea@davea.name> - 2015-04-07 11:04 -0400
        Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-07 09:06 -0600
          Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 08:47 -0700
            Re: Best search algorithm to find condition within a range Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-04-07 20:06 -0400
            Re: Best search algorithm to find condition within a range Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-04-08 12:49 +1200
        Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-08 08:36 +1000
          Re: Best search algorithm to find condition within a range Cameron Simpson <cs@zip.com.au> - 2015-04-08 08:51 +1000
        Re: Best search algorithm to find condition within a range Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-04-07 20:01 -0400
        Re: Best search algorithm to find condition within a range albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-04-18 18:08 +0000
          Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-19 23:02 +1000
            Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-19 17:56 +0300
              Re: Best search algorithm to find condition within a range Gene Heskett <gheskett@wdtv.com> - 2015-04-19 11:17 -0400
              Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-20 12:53 +1000
            Re: Best search algorithm to find condition within a range Dave Angel <davea@davea.name> - 2015-04-19 14:52 -0400
            Re: Best search algorithm to find condition within a range Paul Rubin <no.email@nospam.invalid> - 2015-04-19 13:44 -0700
            Re: Best search algorithm to find condition within a range albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-04-25 14:49 +0000
      Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 09:18 -0700
  Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-07 08:32 -0600
    Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 08:40 -0700
      Re: Best search algorithm to find condition within a range Dave Angel <davea@davea.name> - 2015-04-07 12:33 -0400
        Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 10:07 -0700
          Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-07 11:44 -0600
            Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-08 10:38 +1000
              Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-08 11:18 +1000
                Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-08 08:37 -0600
              Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 23:19 -0700
                Re: Best search algorithm to find condition within a range Mel Wilson <mwilson@the-wire.com> - 2015-04-08 13:39 +0000
                Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-08 07:56 -0700
                Re: Best search algorithm to find condition within a range Mel Wilson <mwilson@the-wire.com> - 2015-04-08 17:33 +0000
                Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-08 12:28 -0700
                Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-08 12:36 -0700
                Re: Best search algorithm to find condition within a range Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-04-08 21:28 +0100
                Re: Best search algorithm to find condition within a range Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-04-08 21:29 +0100
          Re: Best search algorithm to find condition within a range Terry Reedy <tjreedy@udel.edu> - 2015-04-07 14:55 -0400
          Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-07 13:19 -0600
            Re: Best search algorithm to find condition within a range Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-04-07 20:27 +0100
              Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 15:35 -0700
                Re: Best search algorithm to find condition within a range Dave Angel <davea@davea.name> - 2015-04-07 20:38 -0400
                Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-07 17:35 -0600
                Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-08 00:28 -0700
                Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-08 08:35 -0600
                Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-08 00:35 -0700
          Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-08 05:25 +1000
          Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-07 13:28 -0600
          Re: Best search algorithm to find condition within a range Serhiy Storchaka <storchaka@gmail.com> - 2015-04-07 23:57 +0300
          Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-08 10:18 +1000
            Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-08 07:31 +0300
      Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-07 14:15 -0600
      Re: Best search algorithm to find condition within a range Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-04-07 21:42 +0100
    Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-08 08:55 +1000
      Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-07 17:30 -0600
  Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-08 08:57 +1000
    Re: Best search algorithm to find condition within a range Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-04-08 12:59 +1200
      Re: Best search algorithm to find condition within a range Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-04-08 02:39 +0100
      Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 23:12 -0700
    Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-08 11:49 +1000
      Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-09 12:32 +1000
        Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-09 12:39 +1000
          Re: Best search algorithm to find condition within a range wxjmfauth@gmail.com - 2015-04-08 23:14 -0700
    Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-07 22:50 -0700
    Re: Best search algorithm to find condition within a range wxjmfauth@gmail.com - 2015-04-07 23:07 -0700
      Re: Best search algorithm to find condition within a range wxjmfauth@gmail.com - 2015-04-07 23:18 -0700
        Re: Best search algorithm to find condition within a range Denis McMahon <denismfmcmahon@gmail.com> - 2015-04-08 17:27 +0000
          Re: Best search algorithm to find condition within a range wxjmfauth@gmail.com - 2015-04-08 10:50 -0700
    Re: Best search algorithm to find condition within a range BartC <bc@freeuk.com> - 2015-04-08 22:22 +0100
      Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 01:06 +0300
        Re: Best search algorithm to find condition within a range Chris Kaynor <ckaynor@zindagigames.com> - 2015-04-08 17:01 -0700
        Re: Best search algorithm to find condition within a range BartC <bc@freeuk.com> - 2015-04-09 10:19 +0100
          Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 13:00 +0300
            Re: Best search algorithm to find condition within a range Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2015-04-09 13:57 +0200
              Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 15:45 +0300
                Re: Best search algorithm to find condition within a range Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2015-04-09 14:56 +0200
                Re: Best search algorithm to find condition within a range Dave Angel <davea@davea.name> - 2015-04-09 09:19 -0400
                Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 16:33 +0300
                Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 16:49 +0300
                Re: Best search algorithm to find condition within a range Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2015-04-09 15:57 +0200
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 00:08 +1000
                Re: Best search algorithm to find condition within a range Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2015-04-09 16:53 +0200
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 01:02 +1000
                Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-09 08:12 -0700
                Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-10 01:21 +1000
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 01:36 +1000
                Re: Best search algorithm to find condition within a range MRAB <python@mrabarnett.plus.com> - 2015-04-09 17:40 +0100
                Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-09 07:54 -0700
                Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-09 09:03 -0600
                Re: Best search algorithm to find condition within a range jonas.thornvall@gmail.com - 2015-04-09 08:21 -0700
                Re: Best search algorithm to find condition within a range Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-09 10:23 -0600
                Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-10 01:11 +1000
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 01:34 +1000
                Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-10 02:15 +1000
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 02:36 +1000
                Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-10 03:49 +1000
                Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 19:25 +0300
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 02:43 +1000
                Re: Best search algorithm to find condition within a range Grant Edwards <invalid@invalid.invalid> - 2015-04-09 16:53 +0000
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 03:00 +1000
                Re: Best search algorithm to find condition within a range Grant Edwards <invalid@invalid.invalid> - 2015-04-09 17:44 +0000
                Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-10 03:41 +1000
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 04:07 +1000
                Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 21:14 +0300
                Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 21:11 +0300
                Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 20:43 +0300
                Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-10 03:35 +1000
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 03:56 +1000
                Re: Best search algorithm to find condition within a range Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-10 23:18 +1000
                Re: Best search algorithm to find condition within a range Chris Angelico <rosuav@gmail.com> - 2015-04-10 23:41 +1000
                Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 21:15 +0300
                Re: Best search algorithm to find condition within a range Rustom Mody <rustompmody@gmail.com> - 2015-04-10 09:39 -0700
                Re: Best search algorithm to find condition within a range Marko Rauhamaa <marko@pacujo.net> - 2015-04-09 16:28 +0300

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