FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in          Games  Calendar Log in to check your private messages    Technique Hierarchy          Sudoku Programmers Forum Index -> Solving sudoku View previous topic :: View next topic   Author Message daj95376 Joined: 05 Feb 2006 Posts: 349 : Items Posted: Wed May 03, 2006 5:56 pm    Post subject: Technique Hierarchy I've learned from this forum (and Ruud's technique examples) that you get different solutions to the same puzzle depending on the order in which you apply the techniques. Here is the order that I've chosen for my first ten techniques. (Actually, I've only completed eight of them). Code: * Naked  Single * Hidden Single * Naked  Pair * Naked  Triple * Hidden Pair * Hidden Triple * Locked Candidates (1) * Locked Candidates (2)   Naked  Quad   Hidden Quad I chose this ordering to eliminate having multiple Locked Candidates chosen when applying a single naked/hidden pair/triple would (sometimes) suffice. Other than speed, which doesn't interest me unless it's really bad, does anyone have an argument for a different ordering? Thanks! ===== ===== ===== I know that a generic row/column/block is called a unit and other names. When talking about a 3-cell group in a row/column/block, does it have a name? Back to top Ruud Site Admin Joined: 17 Sep 2005 Posts: 708 : Location: Netherlands Items Posted: Wed May 03, 2006 6:27 pm    Post subject: daj95376 wrote: does anyone have an argument for a different ordering? I have locked candidates before pairs and triples. A pair of locked candidates that isolates a hidden single should be high on the list, maybe even before the naked single, because for a naked single you need pencilmarks, but not for a hidden single revealed by locked candidates. Quote: I know that a generic row/column/block is called a unit and other names. When talking about a 3-cell group in a row/column/block, does it have a name? The names "minirow" and "minicolumn" have been used. You can also use the term "intersection" for the 3 cells. Ruud. _________________ Meet me at sudocue.net Back to top ajb Joined: 18 Mar 2006 Posts: 18 : Items Posted: Mon May 15, 2006 11:35 pm    Post subject: Re: Technique Hierarchy daj95376 wrote: I've learned from this forum (and Ruud's technique examples) that you get different solutions to the same puzzle depending on the order in which you apply the techniques. Here is the order that I've chosen for my first ten techniques. (Actually, I've only completed eight of them). Why not have it so that you can choose which techniques you apply? That's what I have done with my software, which is available here: http://uk.geocities.com/aidan_001/software.html Back to top angusj Site Admin Joined: 18 Jun 2005 Posts: 406 : Items Posted: Tue May 16, 2006 12:33 am    Post subject: Re: Technique Hierarchy daj95376 wrote: I've learned from this forum (and Ruud's technique examples) that you get different solutions to the same puzzle depending on the order in which you apply the techniques. That is definitely not correct. A properly formed puzzle can only have one solution. However you can arrive at that solution via many different routes. Back to top rkral Joined: 21 Oct 2005 Posts: 233 : Items Posted: Tue May 16, 2006 12:58 am    Post subject: Re: Technique Hierarchy angusj wrote: daj95376 wrote: I've learned from this forum (and Ruud's technique examples) that you get different solutions to the same puzzle depending on the order in which you apply the techniques. That is definitely not correct. A properly formed puzzle can only have one solution. However you can arrive at that solution via many different routes. And sometimes one route actually leads to the solution, while another leaves the puzzle unsolved. Back to top gsf Joined: 18 Aug 2005 Posts: 411 : Location: NJ USA Items Posted: Tue May 16, 2006 1:12 am    Post subject: Re: Technique Hierarchy angusj wrote: daj95376 wrote: I've learned from this forum (and Ruud's technique examples) that you get different solutions to the same puzzle depending on the order in which you apply the techniques. That is definitely not correct. A properly formed puzzle can only have one solution. However you can arrive at that solution via many different routes. I think "solutions" was a poor choice of words the intent was probably "traces of techniques leading to a solution" Back to top daj95376 Joined: 05 Feb 2006 Posts: 349 : Items Posted: Tue May 16, 2006 4:37 am    Post subject: Re: Technique Hierarchy angusj wrote: daj95376 wrote: I've learned from this forum (and Ruud's technique examples) that you get different solutions to the same puzzle depending on the order in which you apply the techniques. That is definitely not correct. A properly formed puzzle can only have one solution. However you can arrive at that solution via many different routes. I apologize for an improperly worded statement. What I intended to say was that applying techniques in different hierarchies can result in different solution paths to the solution. Back to top Volker1953_Hamburg Joined: 23 May 2006 Posts: 4 : Items Posted: Tue May 23, 2006 11:18 pm    Post subject: I suggest to repeat first NakedSingles HiddenSingles NakedSingles HiddenSingles ... until they don't solve anymore, because they are depending. Back to top qbarryg Joined: 15 Apr 2006 Posts: 5 : Items Posted: Sat May 27, 2006 7:28 pm    Post subject: Order of techniques My solver is still fairly primitive and looking at other's posts probably poorly tought out. Mine goes: Pinned Forced Locked Set(s) of equal number of values set. Intersections. Locked Set(s) of oddball number of values sets. x-wing unique rectangles (type 4 is not implemented) xy-wing xyz-wing BUG simple coloring remote pairs Fall back to a very dumb guessing routine. Fall back to brute force. At the very least some of my algorithms could be changed to only do a minimal set. They all could use some optimization. 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