Finding a puzzle based on known given squares

Everything about Sudoku that doesn't fit in one of the other sections

Re: Finding a puzzle based on known given squares

Postby denis_berthier » Fri May 15, 2020 3:51 am

m_b_metcalf wrote:
denis_berthier wrote:Anyway, I find this puzzle very interesting. It has very few minimals compared to the other hard ones.
You might be interested in a pattern that was used in both games 1 and 39 in 'Patterns Game 1.0' (pages 1 and 99), again devised by jpf.
Code: Select all
 . . . 6 . . . . .
 5 7 4 1 . . . 3 .
 2 . . . . . 1 8 5
 . . . . . . . 4 .
 . . . . 5 . . . .
 . 1 . . . . . . .
 6 3 9 . . . . . 2
 . 8 . . . 9 5 7 6
 . . . . . 4 . . .
It yields only five known valid puzzles:


I see. I tried it, but I got nothing after 30 minutes, so I killed the process.

However, the underlying pattern (...X.....XXXX...X.X.....XXX.......X.....X.....X.......XXX.....X.X...XXXX.....X...) gave me this, after some 20 minutes:
...3.....7548...3.6.....215.......4.....9.....7.......398.....4.6...2578.....6... # 16 FN C23.m/S2.p
(probably a morph of some of the 5 known ones)

What makes the Metcalf-B7B (I've seen no other name, so I got used to name it so) so different to me is, the pattern itself doesn't yield much compared to the other hard ones. Though I guess it doesn't matter in a top-down search for the hardest, as the digits are given.
denis_berthier
2010 Supporter
 
Posts: 1545
Joined: 19 June 2007
Location: Paris

Re: Finding a puzzle based on known given squares

Postby m_b_metcalf » Fri May 15, 2020 7:40 am

denis_berthier wrote:However, the underlying pattern (...X.....XXXX...X.X.....XXX.......X.....X.....X.......XXX.....X.X...XXXX.....X...) gave me this, after some 20 minutes:
...3.....7548...3.6.....215.......4.....9.....7.......398.....4.6...2578.....6... # 16 FN C23.m/S2.p
(probably a morph of some of the 5 known ones)

I should have written that there are only five known ratings rather than five known puzzles. This is a different puzzle but has the same 1.2 rating as the first of the others.

Regards,

Mike
User avatar
m_b_metcalf
2017 Supporter
 
Posts: 10984
Joined: 15 May 2006
Location: Berlin

Re: Finding a puzzle based on known given squares

Postby coloin » Wed May 20, 2020 2:32 pm

I guess these sorts of puzzle generators like gsf's program - the speed of production depends on the number of ED puzzles which have that particular pattern.
The 23C pattern used in patterns game 1 and 39 with only 3 clues in the middle band actually has over 23000 ED minimal/ mostly non-minimal puzzles, but apparently only 5 different ratings.
Normally these generators would produce many more puzzles much more rapidly , as a more average pattern with 23C might have 1 billion ED puzzles.

In the finite world of sudoku puzzles .....this may well be the same process in the pattern from m_b_metcalf puzzle [ I think it has inherited that tag] ... as this has only 20C it wil have much less puzzles than the 22C patterns in eleven#3 and eleven#22,
Udate
My generation process has stopped at only 112 ED all minimal puzzles for the 20C pattern of the m_b_metcalf puzzle no wonder they were hard to come by !
coloin
 
Posts: 1906
Joined: 05 May 2005

Previous

Return to General