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Re: Sudoku solver

From Christian Gollwitzer <auriocus@gmx.de>
Newsgroups comp.lang.python
Subject Re: Sudoku solver
Date 2015-03-30 09:13 +0200
Organization A noiseless patient Spider
Message-ID <mfat14$v08$1@dont-email.me> (permalink)
References (4 earlier) <R6HRw.1255136$4b6.945049@fx44.am4> <55176c2c$0$13009$c3e8da3$5496439d@news.astraweb.com> <ziRRw.1732061$BB2.522910@fx35.am4> <87619j7kbu.fsf@elektro.pacujo.net> <mailman.334.1427698246.10327.python-list@python.org>

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Am 30.03.15 um 08:50 schrieb Ian Kelly:
> On Sun, Mar 29, 2015 at 12:03 PM, Marko Rauhamaa <marko@pacujo.net> wrote:
>> Be careful with the benchmark comparisons. Ian's example can be solved
>> with the identical algorithm in eight different ways (four corners, left
>> or right). I ran the example with my recent Python solver and got these
>> times in the eight cases:
>>
>>      884   s
>>        2.5 s
>>       13   s
>>      499   s
>>        5.9 s
>>      128   s
>>     1360   s
>>       36   s
>
> That sounds to me like either a transcription error was made to the
> puzzle at some point, or there's something wrong with your solver. The
> whole point of that example was that it was a puzzle with the minimum
> number of clues to specify a unique solution.

I think Marko meant, that if he creates symmetrically equivalent puzzles 
by rotating / mirroring the grid, he gets vastly different execution 
times, but ends up with the same solution. This is not surprising. The 
brute force algorithm branches into different solutions first, then, 
because it fills the grid always in the same order. To compare different 
solvers, it would indeed make sense to average over all symmetric 
solutions to make sure that no solver wins the competition by sheer 
luck, i.e. choosing the right path immediately.

	Christian

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Thread

Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-25 13:39 +0200
  Re: Sudoku solver John Ladasky <john_ladasky@sbcglobal.net> - 2015-03-25 11:44 -0700
    Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-25 13:05 -0600
    Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-25 21:37 +0200
      Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-25 14:09 -0600
        Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-25 22:31 +0200
          Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-26 09:40 +1100
          Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-25 18:07 -0600
            Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-27 20:04 +0000
          Re: Sudoku solver Abhiram R <abhi.darkness@gmail.com> - 2015-03-26 08:26 +0530
          Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-25 21:24 -0600
          Re: Sudoku solver Abhiram R <abhi.darkness@gmail.com> - 2015-03-26 08:58 +0530
            Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-26 14:13 +0200
              Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-26 16:15 +0200
          Re: Sudoku solver albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-04-10 23:10 +0000
      Re: Sudoku solver Sayth <flebber.crue@gmail.com> - 2015-03-27 20:39 -0700
        Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-28 23:50 +0000
          Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-29 11:12 +1100
            Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-29 21:59 +0100
              Re: Sudoku solver Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-29 22:19 +0100
                Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-29 22:59 +0100
          Re: Sudoku solver Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-29 14:06 +1100
            Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-29 15:10 +1100
              Re: Sudoku solver Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-29 21:35 +1100
                Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-29 21:54 +1100
                Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-29 13:01 +0100
                Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-29 16:23 +0100
            Re: Sudoku solver Christian Gollwitzer <auriocus@gmx.de> - 2015-03-29 09:57 +0200
              Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-30 11:54 +0100
            Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-29 12:25 +0100
              Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-29 21:03 +0300
                Re: Sudoku solver Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-29 19:26 +0100
                Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-29 21:33 +0300
                Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-29 22:11 +0100
                Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-30 00:50 -0600
                Re: Sudoku solver Christian Gollwitzer <auriocus@gmx.de> - 2015-03-30 09:13 +0200
                Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-30 01:29 -0600
                Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-30 12:16 +0300
                Re: Sudoku solver Dave Angel <davea@davea.name> - 2015-03-30 04:16 -0400
                Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-30 02:57 -0600
                Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-30 20:13 +1100
          Re: Sudoku solver Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-29 22:21 +0100
            Re: Sudoku solver BartC <bc@freeuk.com> - 2015-03-29 23:17 +0100
              Re: Sudoku solver Seymore4Head <Seymore4Head@Hotmail.invalid> - 2015-03-29 21:40 -0400
  Re: Sudoku solver Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-26 09:50 +1100
    Re: Sudoku solver Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-25 23:04 +0000
      Re: Sudoku solver Christian Gollwitzer <auriocus@gmx.de> - 2015-03-27 07:40 +0100
  Re: Sudoku solver "Frank Millman" <frank@chagford.com> - 2015-03-26 10:19 +0200
    Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-26 14:26 +0200
      Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-26 23:37 +1100
      Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-26 07:15 -0600
        Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-26 16:23 +0200
          Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-26 09:06 -0600
            Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-26 17:48 +0200
              Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-26 10:20 -0600
                Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-26 18:47 +0200
      Re: Sudoku solver Dave Angel <davea@davea.name> - 2015-03-26 10:14 -0400
      Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-27 01:41 +1100
      Re: Sudoku solver Dave Angel <davea@davea.name> - 2015-03-26 11:03 -0400
        Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-26 17:42 +0200
          Re: Sudoku solver Pete Forman <petef4+usenet@gmail.com> - 2015-03-26 22:24 +0000
      Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-27 02:21 +1100
      Re: Sudoku solver Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-03-26 20:42 -0400
      Re: Sudoku solver Dave Angel <davea@davea.name> - 2015-03-27 09:14 -0400
      Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-28 00:25 +1100
      Re: Sudoku solver "Frank Millman" <frank@chagford.com> - 2015-03-27 15:35 +0200
        Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-27 15:56 +0200
          Re: Sudoku solver Dave Angel <davea@davea.name> - 2015-03-27 10:09 -0400
            Re: Sudoku solver sohcahtoa82@gmail.com - 2015-03-27 11:18 -0700
              Re: Sudoku solver Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-28 12:46 +1100
            Re: Sudoku solver Larry Hudson <orgnut@yahoo.com> - 2015-03-27 16:48 -0700
          Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-28 01:07 +1100
          Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-28 01:19 +1100
            Re: Sudoku solver Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-03-28 14:13 +1300
            Re: Sudoku solver Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-28 12:40 +1100
              Re: Sudoku solver Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-28 02:24 -0600
          Re: Sudoku solver Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-27 16:03 +0000
          Re: Sudoku solver Virgil Stokes <vs@it.uu.se> - 2015-03-28 19:36 +0100
      Re: Sudoku solver Dave Angel <davea@davea.name> - 2015-03-27 09:48 -0400
      Re: Sudoku solver Dave Angel <davea@davea.name> - 2015-03-27 09:52 -0400
      Re: Sudoku solver Chris Angelico <rosuav@gmail.com> - 2015-03-28 00:58 +1100
  Re: Sudoku solver mr.smittye@gmail.com - 2015-03-29 16:39 -0700
    Re: Sudoku solver Marko Rauhamaa <marko@pacujo.net> - 2015-03-30 12:24 +0300

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