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Meanings of puzzle ratings
https://www.calcudoku.org/forum/viewtopic.php?f=2&t=854		 Page 2 of 2
Author:  paulv66  [ Wed Jan 04, 2017 5:36 pm ]
Post subject:  Re: Meanings of puzzle ratings
jpoos wrote:
paulv66 wrote:
Size n! n!^n Rating
...
7 5040 8.26064E+25 59.68
...

There must be something wrong with the above logic, as I know I've seen at least one 9x9 with a rating of 130+.


If you want to be sure, todays 7x7 difficult also has a rating of 64.7.


I'm sure Patrick will explain. I've just re-read his post and he talks about averaging the number of possible combinations in each row and column, which would bring us back to n! instead of n!^n, so my logic is definitely flawed.
Author:  jpoos  [ Wed Feb 24, 2021 5:47 pm ]
Post subject:  Re: Meanings of puzzle ratings
I would like to bump this thread again. Patrick, if it's not too much to ask, could you provide us with an explicit example of a rating calculation?

In the paper previously mentioned (http://www.calcudoku.org/papers/choice_ ... _v1.01.pdf), you say that the 4x4 on the second page has a rating of 0. This would mean that every row/column only has 1 'possible' permutation. I can see why that would be the case for the columns, but not for the rows. For example, in the top row, you initially don't know the ordering of the 2 and the 4 in the 6+ cage, unless we also consider other cages.

Of course, we also still have the problem of ratings exceeding the maximum possible rating. Todays 4x4 difficult has a rating of 15.7, which is higher than anything I would ever calculate.
Author:  pnm  [ Thu Feb 25, 2021 12:24 pm ]
Post subject:  Re: Meanings of puzzle ratings
jpoos wrote:
I would like to bump this thread again. Patrick, if it's not too much to ask, could you provide us with an explicit example of a rating calculation?


I can't, really: one of the key problems when generating puzzles is determining how difficult they are.

If I'd publish an exact calculation, anyone could use it to determine a puzzle's difficulty.

This is also the reason why the formula used to compute the rating on the page is different
(and not as good as the "real" formula).

(The other key problem is guaranteeing a unique solution, in my opinion).
Author:  jpoos  [ Thu Feb 25, 2021 1:01 pm ]
Post subject:  Re: Meanings of puzzle ratings
Ah, I didn't realise this was a secrecy thing, I understand your point.
Author:  pnm  [ Thu Feb 25, 2021 6:16 pm ]
Post subject:  Re: Meanings of puzzle ratings
jpoos wrote:
Ah, I didn't realise this was a secrecy thing, I understand your point.


yes, if I exaggerate this, then I could open-source the software to the site and for creating puzzles,
and then find other similar sites and books popping up.. [mellow]
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