SudokuSolver Forum

A forum for Sudoku enthusiasts to share puzzles, techniques and software
It is currently Fri Mar 29, 2024 1:16 pm

All times are UTC




Post new topic Reply to topic  [ 22 posts ]  Go to page Previous  1, 2, 3
Author Message
PostPosted: Wed Jun 04, 2008 12:32 pm 
Offline
Expert
Expert

Joined: Mon Apr 21, 2008 6:23 am
Posts: 113
Location: Germany
rcbroughton wrote:
Just implemented it in SudokuSolver...

Wow, that was impressively quick! Great work, Richard! ;clapclap;

Look forward to getting my hands on the next version and seeing it in action!

_________________
Cheers,
Mike


Top
 Profile  
Reply with quote  
PostPosted: Thu Jun 05, 2008 5:54 pm 
Offline
Expert
Expert

Joined: Mon Apr 21, 2008 6:23 am
Posts: 113
Location: Germany
Jean-Christophe wrote:
mhparker wrote:
Incidentally, that's why I mentioned Aligned Pair Exclusion, because (although I haven't analyzed it in detail yet) I thought it may be one of the few remaining mainstream vanilla techniques that stands a chance of catching some eliminations that might currently be missed.


Not quite true... APE are already caught by ALS-XZ as explained in Sudopedia.

Thanks for pointing that out, J-C. I had not read this Sudopedia article before, and had mainly learnt about APE from Andrew Stuart, who describes it (in his book "The Logic of Sudoku") as a "beautiful strategy", with no mention of its equivalence to ALS-XZ (which, rather strangely, he chose to discuss before APE). However, in his online Scanraid solver, he checks for APE first, which (in the light of what you say) is probably just as well...

The Sudopedia article, however, just mentioned the equivalence of simpler cases of APE to ALS-XZ, although in practice all 5 or 6 examples of APE eliminations I've examined in the last couple of days (including a couple of more complicated scenarios) are also catchable via ALS-XZ. So I'm wondering whether APE really is a true subset of ALS-XZ. If so, I'd love to see a proof (assuming I could understand it, that is! :) ).

BTW, I didn't realize until recently just how powerful ALS-XZ is. For example, the most "recent" Daily Nightmare (from February 17, 2008) can be done with just basic techniques (singles/intersections/naked+hidden subsets) plus ALS-XZ. I expect this applies to many other Nightmares, too. The bad news is, how does one "spot" these beasts?

_________________
Cheers,
Mike


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 22 posts ]  Go to page Previous  1, 2, 3

All times are UTC


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group