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Solving guide feedback

 
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The Ostrich

Joined: 20 Apr 2006
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PostPosted: Thu Sep 07, 2006 10:44 pm    Post subject: Solving guide feedback Reply with quote

Hi,

With my new Sudoku program, I've written a couple of solving guides which are on my website. They aren't intended to be complete (merely to cover the techniques that Sudoku Tiger is aware of), but I hope the clarity of the graphics and example-driven style makes up for it.

www.sudokutiger.com/Hint_Sudoku.htm
www.sudokutiger.com/Hint_Killer.htm

Any feedback would be appreciated.
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TheSpaniard

Joined: 28 Aug 2006
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PostPosted: Fri Sep 08, 2006 1:48 pm    Post subject: Reply with quote

Buenos dias, The Ostrich.

I have had a look to your Web page. It is well structured, and easy to follow. The solving guide is well explained and easy to understand.
I haven't tried the software yet, but I agree with you that the techniques you mentioned are the maximum one human player can understand and use when solving a Sudoku (although maybe you must consider including Swordfish, as the spotting procedure is the same than X-Wing).

I have one comment and one suggestion to make you.

a) The comment: In your solving guide, when you speak about Multicolors (Type 2), the example is unfortunate, thus you don't need at all multicolors to solve that position: It's Normal Colors. Maybe should be better to use a position in which Multicolors Type 2 actually was the only possibility to finish the puzzle.

b) The suggestion: You are right when you said that Multicolors is complicated to spot by humans, much more than Colors, indeed. Have you read the first post of my thread about "Formal Definition of Unified Colors Technique"? In this post I describe, in human terms, as well than in computer terms, an extension of Colors methos that, with one single more step (that I call the X-Ray technique), unifies BOTH Colors and Multicolors in one single technique. And, I insist that it is very easy to spot by humans.
In fact, X-Colors can spot X-Wing too, so, as you don't include Swordfish and other Seafood in your solver, you can substitute the three techniques with Expanded Colors (or X-Colors), that will even allow the players to find a solution to some puzzles that they cannot be solved using this three techniques all together.

Well, it is only a suggestion.

Congratulations for your web page.

Saludos
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The Ostrich

Joined: 20 Apr 2006
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PostPosted: Mon Sep 11, 2006 12:45 pm    Post subject: Reply with quote

Its a matter of definition. I use the following (said by bart http://www.setbb.com/phpbb/viewtopic.php?p=2575&mforum=sudoku):

Quote:

and I quote agnus on this one:

Simple Colors
coloring one conjugate chain on a single candidate

Multi Colors
coloring more than one conjugate chain on a single candidate

Advanced Colors
coloring more than one conjugate chain on more than one candidate


I think that it makes no sense at all to call something requiring many colours simple colouring, as distinguished from multi-colouring which uses many digits. It seems to me that "multi-digit colouring" or "advanced colouring" are better terms for multiple candidate extensions.

Under the above definition, you do require multiple colours for drawing the cojugate chains, so it is multi-colouring. And if you think I'm the only person who sees it that way, look here:

http://www.angusj.com/sudoku/hints.php

Of course, you say that "X-Colors can spot X-Wing too"...

Well, it seems to me, and I think probably to most people that the Type-1 multi colouring rule: "If any two labels from different chains share a group, then any cell sharing a group with both their conjugates cannot contain the digit" will spot X-wings automatically. Speaking of which, I have made an error on my website, which I will correct...
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TheSpaniard

Joined: 28 Aug 2006
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PostPosted: Fri Sep 22, 2006 10:08 am    Post subject: Reply with quote

To The Ostrich:

Matter 1: (my feedback comment on your Web).
Your example of Multicoloring type 2 IS DEFINITELY NOT an example of Multicoloring Type 2 at all.
Sorry, but, following your own definition, this example is a clear "Type 2 Single Coloring". All cells marked "A" can be eliminated, because two of them shares the same house (column 1), so cells marked "A*" are definitely true... without any need of multicoloring.
If you want that your solving guide could be a must... I suggest you to be a little more accurate.

Matter 2: (my suggestion on X-Colors).
I haven't any need of convince anyone if X-Colors is or is not a valuable technique. If people prefers using other techniques, perfect.
I personally use it, it works, I personally think it is easy enough to spot in human solving, and I gratefully shared that with the community. That's all.
If you think it is unuseful, Ok, don't use it. Nothing to say about it.

The only thing I ask is that, when you reply and comment things, at least you should have read and understand these things before writing about it.

Please note that:
X-Colors is not a multicoloring technique (it only needs TWO colors), and
X-Colors overrides both Single Colors AND Multiple Colors techniques in only one technique.
As a bonus, X-Colors can solve some situations in which both Single and Multiple Colors cannot.
As you don't use Swordfish, nor other nxn techniques, I even mentioned the obvious thing that X-Colors can spot X-Wing too... due to the fact that Multicolors can do it too, and X-Colors overrides Multicoloring.
And, last of all, X-Colors works only on individual candidates, so it is not, and it can't never be an "Advanced Colors" technique.

Best regards.
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The Ostrich

Joined: 20 Apr 2006
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PostPosted: Mon Sep 25, 2006 5:51 pm    Post subject: Reply with quote

Sorry,

You're ~ correct. The type-2 multicolouring example is indeed also an example of type 2 single colouring. Of course, it is ALSO an example of type 2-multi colouring, which can be used to eliminate exactly the same cells, but it isn't necessary if you look for single-colouring as well. So saying:

Quote:

Your example of Multicolouring type 2 IS DEFINITELY NOT and example of Multicolouring Type 2 at all


is a bit misleading. This isn't an inaccuracy in the solving guide - but it isn't a good example. I'll replace it with a better one shortly. I'll investigate why the program spots the multi-colour elimination rather than the single-colour one, too, since this is a bug.

Thanks for the feedback.
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TheSpaniard

Joined: 28 Aug 2006
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PostPosted: Tue Sep 26, 2006 7:26 pm    Post subject: Reply with quote

The Ostrich:

You're welcome.

Buenas noches.
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